182 Illinois State Laboratory of Natural History. 



One of the most interesting of those noticed is a small cy- 

 lindrical worm with a retractile caudal (?isc from which arise 

 four ciliated tentacles. It lives in great numbers in tubes on 

 the under side of lily pads in Lily Lake, and when undisturbed 

 lies with the hind end of the body out of the tube and, with 

 the disc and tentacles expanded, sways slowly about. It will 

 probably prove to be Dero intermedins, Cragin, though it is 

 questionable if this is more than a variety of D. digitata, Mull. 



Leeches which I have provisionally separated as five species 

 were taken from the sloughs. All appear to belong to the 

 genus Clepsine. Several of them were very common, being 

 brought in on the shells of turtles, and at other times appar- 

 ently attached to fishes. 



Quite a variety of rotifers were observed, but none of 

 special interest except the large and beautiful Conochilus volrox, 

 colonies of which, consisting of a dozen or more individuals, 

 were common in the open water of the bay, where they could 

 always be taken in surface nets drawn after a skiff. 



Flumatella arethusa^ Hyatt. 



(Hyatt, Observations on Polyzoa, 95.) 



One of the branching polyzoans was very common in most 

 of the pools, sometimes on sticks, on the under side of stones, 

 and, in Lily Lake, on the under side of the lily pads. The 

 statoblasts were frequently noticed scattered among alga' and 

 rubbish. 



Hyalinella vesicularis, Leidy. 



(Pliimatella vesicularis, Leidy, Proc. Acad. Nat. Sci. Phil., 

 vii, 102.) 



A single example of a small colony from Libby Lake, is re- 

 ferred to this species with some doubt. 



Pectinatella maf/ni/ica^ Leidy. 



{Cristatella magnijica, Leidy, Proc. Acad. Nat. Sci. Phil., 

 V, 265.) 



The large masses of gelatinous matter so common in "back 

 water" in this region, are formed by the colonies of this poly- 



