374 DESCRIPTION OF {Rotatoria. 



styles are advanced, which is the case when preparing to 

 leap. Found with Hydatina senta and Brachionus urceo- 

 laris. Length, without cirri, 1-1 40th. 



637. Triarthra mystacina {Brachionus passus, M.) 

 The short-bearded Triarthra. — Eyes close together; two 

 anterior cirri, or bristles, and foot, nearly double the 

 length of the body ; jaws very soft. Found in water-tubs. 

 Length 1-2 16th. 



Genus CLX. Rattulus. The rat Rotatoria have two 

 frontal eyes, and a simple styliform foot, but no cirri, or 

 beard. Several undefined rotatory muscles, an cesophagal 

 head, without distinct teeth or oesophagal tube, a simple 

 conical ahmentary canal, with two round glands, an 

 ovarium, and eyes, comprise the organization at present 

 discovered. 



638. Rattulus luuaris {Trichoda lunaris, M.) The 

 sickle-shaped Rattulus. — Body small; eyes remote from the 

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

 Group 409 represents two of these animalcules. Found 

 in turfy pools. Length 1 -288th. 



Genus CLXL Distemma. The double-star Rotatoria 

 have two cervical eyes and a forked foot ; the vibratile 

 organ is compound. The nutritive apparatus consists of 

 an oesophagal head, which in three species has jaws, with 

 two teeth each ; in one species more than two, a short 

 oesophagal tube, and a simple conical alimentary canal, with 

 two spherical glands. The reproductive organs are an 

 ovarium, and in D. ( ?) marinum sexual glands and a con- 

 tractile vesicle. No satisfactory details of a vascular system 

 are ascertained, but that of sensation is illustrated by the 

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



