allied to the genus Notommata of Ehrenberg. 155 



The female preys on other Infusoria and Rotifera, and even 

 on its own kind. Its most common food appears to be Infusoria 

 of the genus Gonium, the cells of the stomach being constantly 

 found distended with these animals. Large spinous Rotifers, 

 such as Brachionus Bakeri, are not unfrequently seen entire in 

 the stomach. The half or wholly digested food of the animal is 

 rejected through the oesophagus. 



The female is about half a line in length, and may be detected 

 by the naked eye. The motion in swimming is slow and graceful, 

 and the animal, having no prehensile organ, of course never 

 rests. 



The jaws of the female (see fig. 5) are curiously toothed, but 

 seem more calculated for nipping and holding than for mastica- 

 tion. 



The male animal (see PI. VI. fig. 2) is about half the size of 

 the female, and differs from it in form, being much shorter and 

 of a rude triangular shape. It is more difficult to detect than 

 the female, being exceedingly transparent, and from the empti- 

 ness of the body appearing little more than a transparent ciliated 

 bubble. It is very active, and occasionally puffs out the sides of 

 its body, so as entirely to alter its form, and remains thus dis- 

 tended some time. 



On the most careful examination of the males we have never 

 been able to discover any jaws, gullet, stomach, or hepatic organs 

 in them, nor any appearance whatever of extraneous matter being 

 received into the body. 



At the bottom of the body on one side is a conspicuous round 

 sperm-vessel or testis, in which, under a high power, spermatozoa 

 in active vibratile motion may be seen, and at its external side a 

 duct, closed by distinct lateral muscles. Connected with the 

 testis is a well-defined intromittent organ and a conspicuous pass- 

 age or opening for its extrusion from the body of the animal. In 

 the opposite lower angle are three small irregularly-formed kid- 

 ney-shaped bodies connected with an angular lobe or muscle 

 lying beneath them. The male is also furnished with the deli- 

 cate membranous plicated bag and rudiments of the curled tu- 

 bular structure found in the female. 



Observations upon the Ova. 



June \5th. — Placed a female in a trough, having one of the 

 transparent ova above and a dark ovum beneath in its body. 



June \Qthy 8 a.m. — Could not find the dark ovum. The trans- 

 parent ovum remained and was become nearly dark. 



2 p.m. — Found the female dead. Examined the ovum occa- 

 sionally for upwards of a week without perceiving the least 

 change. 



11* 



