History of the Hairy-backed Animalcules. 403 



muscular walls, which terminates at about one-fourtli of the 

 body-length. The perforation is so slender as to be detected 

 only while a morsel is in the act of being swallowed. The 

 intestine presents nothing remarkable, except that in its yel- 

 lowish granular wall containing fat-cells, Dr. Schulze thinks he 

 finds a hepatic function. The body-cavity is occupied by a 

 finely-granular, soft parenchyma, the corpuscles scattered in 

 which are not driven to and fro by the movement of the body, 

 in which therefore a somewhat firm consistence is inferred. 

 No trace of a muscular, nervous, or vascular system was dis- 

 covered, though many individuals were carefully examined. 



The animal is hermaphrodite. A great ovary lies in the 

 posterior half of the body, over the intestine, in the hinder 

 portion of which are contained the incipient egg-germs, con- 

 sisting of vesicle and speck, which are developed in the anterior 

 portion, becoming surrounded with a granular yelk. Generally 

 one or two eggs are found freed from the ovary, enclosed in 

 a special soft colourless envelope. In front of these mature 

 ova lies the spermatic gland, a mulberry-like mass of cells, and 

 close to it two groups of spermatozoid germ-cells, apparently 

 unenclosed, lying free in the parenchyma. In some examples 

 the spermatozoids were developed, but showed no spontaneous 

 motion. 



The specimens described occurred to Dr. Max Schulze in 

 sea-sand from Cuxhaven, with Desmidece and Diatomacece. 

 They swam with a gentle gliding movement, like the Turbel- 

 laria. 



Genus V. — Echinodera (Dujardin) . 



Body articulated; set with few bristles; head distinct; 

 posterior extremity truncate, with two short processes, and 

 spines. 



' Sp. 11. E. Dujardini (Oosse). (PI. ii. Fig. 16.) As the 

 discoverer and describer has not assigned any specific name to 

 his animal. I take the liberty of honouring it with his own. 

 M. Dujardin obtained the form in July, 1841, in sea- water from 

 St. Malo, which had been kept for six months. The generic 

 name, signifying " spinous neck," he selected to show its rela- 

 tions with Echinorhynchus. The body, 0*30 mm. to 055 mm. 

 (about l-75th to l-50th of an inch) long, is oblong, almost 

 cylindrical in front, a little flattened behind, whei'e it terminates 

 by two great bristles, accompanied by two other bristles of 

 smaller size, like those we see at the extremity of the Gyclo- 

 pidce. The body is composed of ten segments, without count- 

 ing the head, which is retractile, bristled with long and flexible 

 spines, and without counting the caudal laminae (lames) which 

 accompany the terminal setae, making the total number of seg- 

 vol. v. — NO. VI. E E 



