150 The Ohio Journal of Science [Vol. XXI, No. 5, 



Tubifex multisetosus (Smith). This genus, possibly about 

 half as abundant in the pond as is Limnodrilus, was fully nine- 

 tenths of this one species. Some specimens Prof. Smith found 

 exceptionally mature and desirable for identification. 



Tubifex tubifex (Muller) = (Tubifex rivulorum Lamarck). 

 A few were identified as very likely of this species. 



Aulodrilus pluriseta Piguet (?). Prof. Smith, who found 

 two specimens of this among my Oligochsets, reports this as 

 the first record of the occurrence in the United States of this 

 genus. While the species is doubtful, it is at least similar to 

 A. pluriseta Piguet, of Switzerland. The position of Aulodrilus 

 is tentative; in fact its family relationships are problematical 

 because its reproductive organs have not been studied. Smith 

 reports that Piguet first put it among the Naididas, and subse- 

 quently among the Tubificidae, where it may remain for the 

 present. 



Apparently it is rare in this pond. Nothing more can be 

 said than that the specimens were obtained with some of 

 Tubifex, D.ero, and Nais, station 11, June 5. Piquet (as Smith 

 reported) describes these worms as living in the little tubes 

 formed by particles of debris, held together by secretions, from 

 the surface layer of the worm. When separated from their 

 tubes they do not use the old ones again, but build new ones. 



Order Megadrili. 



Helodrilus caliginosus var. trapezoides (Duges). This, (Smith '17) 

 the most abundant and most widely distributed American earthworm, 

 abounding in the bottom lands of rivers, as well as less moist earth, 

 was found in Mirror Lake in small number near the shoreline. These 

 and a couple of other Lumbricids, (Helodrilus sp.) taken from the 

 pond, undoubtedly were in the water by accident; hence they are not 

 listed among the aquatic forms. 



Class HiRUDINEA. 



Leeches were well represented in Mirror Lake, considering 

 the small size of the group. 



Order Rhynchobdellida. 



Family Glossiphonidce. 



Glossiphonia stagnalis (Linn.). This, (Moore '12) "abounds 

 especially in warm, shallow waters of streams, pools and ponds; 

 it is the common pond leech." It was the commonest leech in 



