irydatinaea.\ infusoeial animalcules. 645 



Rattdxus limaris {Trichoda lunaris, M.) Body small ; cj-cs remote 

 from the frontal margin. ; foot decurved, lunate. No teeth are seen. 

 Group 409 rcpreseuts tsv'O of those animalcules. Eound in turfy- 

 pools. Length l-288th. 



Genus Distemjia. TJie douhle-star Rotatoria have two cervical eyes 

 and a forked foot ; the rotaiy organ is compound. The nutritive 

 apparatus consists of an oesophageal head, which in three species has 

 jaws, with two teeth each ; in one species with more than two, a 

 short oesophageal tube, and a simple conical alimentary canal, with 

 two spheiical glands. An ovai'ium, and in D. (?) marinum glands 

 and a conti'actilo vesicle are seen. No satisfactory details of a vascular 

 system arc ascertained, but that of sensation is illustrated by the 

 presence of eyes, which are red, except in one species, in which they 

 are colourless. In all the species, except D. marinum, the eyes are 

 sitiiated behind the head of the oesophagus, but in that one they 

 are anterior, but below the rotary organ. The eggs are never 

 attached to the parent, nor are they developed in large masses. 



D. forfcuh. — Body cylindrico-conical ; eyes red ; toes thick, 

 recurved and dentate at the base. The eyes are placed at the 

 end of a long cylindi-ical nervous ganglion ; the rotary organ consists 

 of foiu' parts. Fig. 411 is a side (left) view, and fig, 410 shews 

 the jaws extended for seizing prey. Length 1-1 20th. 



D. setigerum. — Body ovato-oblong ; eyes red; toes setaceous and 

 decurved. Length 1-2 16th. 



D. (?) marinum. — Body ovato- conical; eyes red, close together; 

 foot long ; toes thick, the length of the foot ; jaws many -toothed. 

 Found in sea- water. Length 1 -144th. 



D. (?) forcipatum. — Body ovato-oblong ; eyes coloiu'less ; foot 

 short, with stout toes. If the two colourless vesicles are not eyes 

 it must be placed in the genus Pleurotrocha. Length l-288th. 



Genus TRiopHTHAiMtrs. The roiv-eyed Rotatory Animalcules. — Eyes 

 three, ceiwical, sessile, in a row ; foot forked ; rotatory organ com- 

 pound. It has a large oesophageal head, with two (single-toothed ?) 

 jaws, a long thin oesophagus, a globose stomach-like protuberance, 

 with two oval glands, and thin posterior alimentary canal ; two 

 muscles move the foot. 



