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 oesophagal 

 head, without distinct teeth or oesophagal tube, a simple 

 conical alimentary canal, with two round glands, an 

 ovarium, and eyes, comprise the organization at present 

 discovered. 



638. RATTULUS lunaris (Trichoda lunaris, M.) The 

 siMe-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 CLXI. DISTEMMA. The double-star Rotatoria 

 have two cervical eyes and a forked foot; the vibratile 

 organ is compound. The nutritive apparatus consists of 

 an O3sophagal head, which in three species has jaws, with 

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

 cesophagal 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 



