GENUS PLATYCOLA. 73 I 



Genus XVIII. PLATYCOLA, S. K. 



(Greek, platus, flat ; colerc, to inhabit.) 



Animalcules as in Vaginicola, but the lorica always decumbent and 

 attached throughout one entire side to its fulcrum of support. 



To the type form of this genus, the Vaginicola decmnbens of Ehrenberg, a large 

 number of species recently figured and described by De Fromentel are here added ; 

 all of these are included by him, in his ' Microzoaires,' as representatives of the 

 typical genus Vaginicola. 



Platycola decumbens, Ehr. sp. Pl. XL. Figs. 33 and 34. 



Lorica decumbent, oval, depressed, transparent when young, becoming 

 dark brown when older, not developed anteriorly in a neck-like manner ; 

 body hyaline, considerably exserted during extension, and projected at 

 right angles to the part contained within the sheath. Length of lorica 

 1-280". H.A.B. — Fresh water, on various aquatic plants and animals. 



The author has not unfrequently found small specimens of the pond-snail 

 Planorbis sp., whose shells were almost entirely encrusted with the loricEe of this 

 abundant species. As in Vaginicola and Cothurnia, two zooids are often developed 

 by longitudinal fission within the same domicile. 



Platycola mollis, From. sp. 



Lorica decumbent, bottle-shaped, three times as long as broad, some- 

 what wrinkled and irregular posteriorly, produced anteriorly towards one 

 side into a short and straight, abruptly truncate, not everted neck ; ani- 

 malcule very contractile, yellow, scarcely reaching, when extended, to the 

 aperture of its lorica ; integument finely punctate. Length of lorica, with 

 neck, 1-300". Hab. — Fresh water. 



Platycola dilatata, From. sp. Pl. XL. Fig. 43. 



Lorica broadly bottle-shaped, the breadth almost equalling the total 

 length, bordered round its side of attachment with a frill-like extension of 

 its substance ; neck short, narrow, constricted at its base ; colour pale 

 yellow; animalcule large, subcylindrical, broadest anteriorly, transparent, 

 extensile to a considerable distance beyond the aperture of the lorica ; 

 parenchyma finely granulate. Length of entire lorica X-300". 



Hab. — Fresh water. 



Platycola regularis, From. sp. 



Lorica smooth, elliptical, about one and a half times as long as broad, 

 ventricose, developed anteriorly into a short, narrow, and somewhat dilated 

 neck, which is usually bent slightly upwards, colour pale yellow ; animalcules 

 when contracted ovate, transparent, not yet obsei-ved in their extended 

 state. Length of lorica 1-350". Hab.— Fresh water. 



