366 Illinois State Laboratory of Natural History. 



the body walls are greatly distended. Monostyla and Chy- 

 dorus seem to be their favorite food. 



This form has not been previously listed from the United 

 States. 



Sacculus Gosse. 



Corona with one apex ; tropin inclosed in a mastax, virgate, 

 with unequal mallei ; alimentary canal very large, having 

 eight caeca ; eggs attached after deposition. 



24. S. viridis Gosse. 



This species was scarce, appearing only in surface towings 

 taken at the mouth of Quiver Lake during May, 1896. 



Family SYNCELffiTIDiE. 



Synch^ta Ehrbg. 



Form usually that of a long cone whose apex is the foot ; 

 front furnished with two ciliated auricles ; ciliary wreath of 

 interrupted curves ; foot small, furcate. 



25. S. pectinata Ehrbg. 



This was abundant and widely distributed, being found at 

 all of the substations. It was not found in July, and was 

 noticeably scarcer in June and August. At all other times 

 of the year it was common and often abundant, especially in 

 May and November. The records for each of the two years 

 were substantially alike. This is a very pretty gem in the 

 water, very quick in its movements, darting hither and 

 thither, and consequently difficult to study, but after its 

 characters are once made out it will long be remembered. 



26. S. sty lata Wierz. ('92). 



Found only in the Illinois River and Quiver Lake, from 

 July to October, and again in March; most abundant in 

 October in the river. 



This was also found by Jennings ('94) in Lake St. Clair. 



Family TRIARTHRID^. 



POLYARTKRA EHRBG. 

 Body small, sac-like; skipping appendages, when present, 

 in clusters on the shonMus; eye single, occipital; mastax 

 large and pear-shaped ; tropin forcipate. 



