682 DESCBiPTioN OF [Sotatoritt. 



■which have two frontal eyes, and a simple styliform foot. All the species 

 have, a smooth, flat, and soft lorica, like a tortoise-shell (testula) ; 

 curved at the margin. A double rotatoiy apparatus, a simple conical 

 foot, having a suction disc at the end, and sometimes cilia, are common 

 to all. P. elliptica alone has a hairy frontal process between the 

 wheels. Transverse or longitudinal muscles exist in. all the species. 

 The four-muscled oesophageal head has jaws, Avith teeth in rows in 

 two species (locogompJiia), and double-toothed {zygogomphia) in P. 

 eJliptica ; the alimentary canal is constricted {gasterodeld), and pos- 

 sesses, anteriorly, two glands ; an ovarium is also seen in all the 

 species. Sexual glands and a contractile vesicle are present in 

 P. patina. No evidences of a vascular system have been discovered, 

 and two red frontal points (probably eyes) are the only indications of 

 a system of sensation. 



Pterodina pa^mflt {Brachioniis fatina, M.) — Lorica membranous, or- 

 bicular, and crystalline, slightly scabrous near the broad margin, and 

 excised anteriorly between the wheels. This species is very deKcate 

 and transparent. Fig. 502 represents a side view, and figs. 503 and 

 504 under views ; the latter having the wheels extended, the fonner 

 having them withdrawn, and the anterior margin bent in, so that the 

 eyes appear near the middle of the lorica. Found in summer, among 

 Lenina and Ceratophyllum. Length about 1-1 20th. 



P. elliptica. — Lorica membranous, elliptical, with a narrow, smooth 

 mai'gin, front entire (not excised). The two wheels united by a 

 brow furnished mth setae. Eyes distant. Found amongst Conferva. 

 Length l-120th to l-108th. 



P. dypeata {Brachionus chjpcatus, M.) — Lorica membranous, oblong, 

 narrow, smooth at the margin ; there is a frontal portion, or brow, 

 connecting the two wheels, but no setae. The eyes approximate. 

 Fig. 505 a dorsal view, with the wheels extended. Foimd in sea- 

 water. Length 1-1 20th; the shell, l-144th. 



The next genus, Pompholgx, instituted by Mr. Gosse, is considered 

 by him a member of this family Brackioncea. 



Genus Pompholtx. (Gosse.) (Ann. I^at. Hist., vol. 8, 1851.) — 

 Two frontal eyes ; foot wanting ; rotatory organ double in the rear, 

 entire in front ; eggs attached behind after deposition. The 



