Genus Plagiophrys Claparède & Lachmann, 1859

 

Below is the original description of Claparède & Lachmann, 1859, and some remarks by Wailes, 1915, about the validity of the generic name.

3e Genre = PLAGIOPHRYS

Les Plagiophrys sont des Actinophryens non cuirassés, munis de nombreux pseudopodes, qui naissent en faisceau d’un seul et même point de la surface du corps. Ces Rhizopodes sont aussi lents dans leur mouvements que les Actinophrys proprement dites. Les pseudopodes laissent voir à leur surface la circulation de granules caractéristique, qui est toutefois fort lente.

 

Plagiophrys cylindrica (V. Pl. XXII, Fig. 1.)

Diagnose : Corps cylindrique, à peu près trois fois aussi long que large.

Le corps de la Plagiophrys cylindrica est recouvert d’une peau à deux contours bien distincts, qu’il n'est cependant pas possible de confondre avec une carapace adhérente. En effet, cette peau est extrêmement flexible, et, par son aspect, rappelle encore plus l’enveloppe externe de la Corycia de M. Dujardin (Amoeba bilimbosa Auerb.) que la cuticule des infusoires. A la base du cylindre cette peau s’amincit et disparaît même complètement, si bien que cette base paraît tout aussi dépourvue de membrane limitant que la surface d’un Actinophrys. Elle est mamelonnée, et c’est d’elle seulement que naissent les pseudopodes. Malgré un examen très-attentif, nous n’avons réussi à reconnaître ni vésicule contractile, ni nucléus. Si cette absence complète de vésicule contractile se confirme, la P. cylindrica formerait un passage évident des Actinophryens aux Echinocystidées.

Nous avons vu cette espèce prendre de la nourriture, et cela précisément de la même manière que le ferait une Actinophrys. Une Astasie (Trachelius trichophorus Ehr.) s’étant approchée imprudemment des pseudopodes y resta agglutinée. Les pseudopodes se raccourcirent, tout en s’étalant de manière à former une enveloppe autour de la proie, tandis qu’une partie de la substance du Rhizopode venait au-devant d’elle pour l’envelopper d’une manière plus intime encore, et l’Astasie finit par être attirée dans l'intérieur même du corps. La proie continua à s'agiter, pleine de vie, pendant près d’une heure, à l’intérieur de la Plagiophrys. L’individu que nous avons représenté renferme à son intérieur une Astasie et une Chroococcacée.

La Pl. cylindrica atteint une longueur d’environ 0mm,13. Nous n’en avons ren­contré qu’une seule fois quelques exemplaires, à Berlin, dans une petite bouteille renfermant de l’eau et des algues de provenance inconnue.

 

2° Plagiophrys sphaerica. (V. Pl. XXII, Fig. 2.)

Diagnose: Plagiophrys à corps exactement sphérique.

Cette espèce est suffisamment caractérisée par la diagnose. C’est une boule d’un point de laquelle naît un faisceau de pseudopodes. Ceux-ci sont beaucoup moins nombreux que dans l’espèce précédente ; nous avons constaté chez eux la possibilité de se souder les uns aux autres. Nous avons reconnu l'existence d’une vésicule contractile. — Diamètre du corps, 0mm,03-0mm,04. Observée dans la Sprée, à l’Unterbaum (Berlin)

 

4e Genre  - PLEUROPHRYS

Les Pleurophrys sont chez les Actinophryens ce que sont les Difflugies chez les Amobéens. Elles sont revêtues d’une coque munie d'une seule ouverture et formée par des substances étrangères agglutinées au moyen d’un ciment organique.

 

Pleurophrys sphaerica (V. Pl. XXII, Fig. 3.)

Diagnose : Coque sphérique, formée par des particules siliceuses.

La Pleurophrys sphaerica ne se distingue de la Plagiophrys sphaerica que par la présence de la coque. La forme de ces deux Rhizopodes est parfaitement la même. Le peu de transparence de la coque ne nous a pas permis de reconnaître l’organisation intérieure. Diamètre, 0mm,02. Dans les tourbières de la Bruyère aux Jeunes-Filles (Jungfernhaide), près de Berlin.

  Translated:

3rd Kind = PLAGIOPHRYS
Plagiophrys are non armored Actinophrys, provided with numerous pseudopodia which radiate from a single point on the surface of the body. These Rhizopods are slow in their movements, just like Actinophrys themselves. The pseudopodia show characteristic slow moving granules on their filopods.

 

1 Plagiophrys cylindrica (V. Pl. XXII, Fig. 1.)
Diagnosis: Cylindrical body, about three times as long as wide.
The body of Plagiophrys cylindrica is covered with a layer of two distinct contours, which cannot be confused with an agglutinated shell. Indeed, this skin is extremely flexible and, in appearance, still remembers the external envelope of Corycia Mr. Dujardin (Amoeba (Cochliopodium) bilimbosa Auerb.) and the cuticle of other protists. At the cylindric base this skin thins and even disappears completely, so that this base seems as limiting membrane devoid of the surface of a Actinophrys. It is hummocky, and from it are born only pseudopodia. Despite a very careful review, we have not been able to recognize a contractile vesicle or a nucleus. If this complete absence of any contractile vesicle can be confirmed, P. cylindrica form a clear passage to Actinophryens Echinocystidées.
We have seen this species take food, and that's precisely the same way as would an Actinophrys do. An Astasia (Trachelius trichophorus Ehr.) which approached recklessly the pseudopodia remained catched. The pseudopods are raccourcirent while stretching to form a wrap around the prey, while a part of the substance of the Rhizopod wrapped it in a more intimate way, and the Astasia ended up being drawn into the inside of the body. The prey continued fussing, full of life, for nearly an hour inside the Plagiophrys. The individual we have represented in its interior contains an Astasia and Chroococcacée.

Pl. Cylindrica reached a length of about 130 µm. We have found it only once some specimens in Berlin, in a small bottle containing water and unknown from algae.

2 Plagiophrys sphaerica. (V. Pl. XXII, Fig. 2.)
Diagnose: Plagiophrys exactly spherical body.
This species is sufficiently characterized by the diagnosis. This is a ball where  pseudopodia radiate from one point. These pseudopodia are far fewer than in the previous species; we found that some specimens could  weld to each other. We recognized the existence of a contractile vesicle. - Diameter of the body, 30-40 µm. Observed in the Spree to Unterbaum (Berlin).

4th Kind - PLEUROPHRYS
The Pleurophrys are among Actinophryens what the Difflugies are in Amobéens. They are coated with a shell provided with one opening and formed by foreign substances agglutinated by means of an organic cement.

Pleurophrys sphaerica. (V. Pl. XXII, Fig. 3.)
DIAGNOSIS: spherical shell, build by siliceous particles.
Pleurophrys sphaerica is only distinguished from Plagiophrys sphaerica by the presence of the shell. The shape of these two Rhizopods is perfectly the same. The lack of transparency of the shell didn't allow us to recognize the internal organization. Diameter, 20 µm. In bogs of the Bruyère Young Girls (Jungfernhaide) near Berlin.

 

Remarks by Wailes, 1915:

A study of the literature relating to this genus, first named Pamphagus by Bailey, has led the assistant author of the present work to the conclusion that the name which should be applied to it is Lecythium. That Pamphagus was pre-occupied was detected by Averintzeff as stated by Schouteden in his annotated abstract in French* of Averintzeff’s Russian memoir of 1906 on the testaceous freshwater Rhizopoda (Conchulina), in which Averintzeff had used the name Pamphagus. Later in the same year, however, he sent to the 'Zoologischer Anzeiger’ a paper in which he proposed for Pamphagus the name Baileya, but although received by the Editor of that journal in October, 1906, it was not printed until February, 1907, Schouteden thus being the first to publish the name. Had no other name been applied to any species of the genus this would have been very appropriate, but between 1853, when Bailey named it, and 1906, when Schouteden published a name in his honour, several generic names had been given to one or other species now included in the genus, and it is necessary to con­sider them.

We may at once dismiss three names used before 1853 : Arcella by Ehrenberg, Gromia by Schlumberger, and Corycia by Dujardin, each founded for species which do not belong to this genus, and the last one cited being pre-occupied. A difficulty arises with the next name to be mentioned, Plagiophrys. It was founded by Claparède and Lachmann for a genus which they describe as “Actinophyrens non cuirasses, munis de nombreux pseudopodes, qui naissent en faisceau d’un seul et meme point de la surface du corps. . . . Ces pseudopodes laissent voir a leur surface la circulation de granules caracteristique, qui est toutefois fort lente.” This is clearly not a definition of the present genus, but how a rhizopod without any test could always emit its pseudopodia from one and the same point on its surface is a puzzle which Archer endeavoured to unravel without coming to a definite conclusion, except that the statement must have been made in error owing to the extreme thinness of the pellicle which renders it almost invisible. Possibly, however, Claparede & Lachmann knew of this pellicle but did not consider it to be of a sufficiently pro­tective nature to serve as a “cuirass.” Two species were included in his genus, P. cylindrica and P. sphaerica. They do not, however, belong to the same genus, the first being considered by Penard to be most probably a Diaphoropodon, and the second appearing to be identical with “Gromia hyalina,” as Ehrenberg’s species was then known. In view of this uncertainty and of the fact that the definition of the genus Plagiophrys, so far as regards this species, is in­correct, we cannot well adopt for it Claparède & Lachmann’s name, which should be relegated to the first of the two species which they describe, namely P. cylindrica.

The next name, Lecythium, was proposed by Hertwig & Lesser in 1874, and the only species which they include in it is L. hyalinum. They give references to former descriptions of the species, and there cannot be any doubt as to its identity. The generic name Lecythium is therefore here adopted.

Although it is unnecessary to pursue the matter further it may be of interest to point out that Platoum, the next name which has been considered a synonym, is of uncertain application; that it was almost imme­diately followed by Chlamydophrys, which would be the name to adopt should Lecythium not stand, and that, even should it fail, we need not fear having to use either of the two uncouth names next proposed, Troglodytes and Phonergates, as both are pre-occupied, Baileya being the next available name on this some­what long list.

* The passage is as follows:—“M. Awerintzew a propose dans le Zoolog. Anzeiger le nom Baileya pour le genre Pamphagus, ce dernier nom etant preoccupe (Insectes).” This was published in the ‘Annales de Biologie lacustre' in December, 1906.