9 8 THE LEECHES OF MINNESOTA 



are completely triannulate ; their annuli and furrows are all equal. 

 Finally XXV is biannulate, XXVI biannulate or uniannulate and 

 XXVII uniannulate. 



It is not at all certain that this is really Verrill's Clepsine occi- 

 dentalis as at least two and perhaps three other species of eight-eyed 

 glossiphonids are found in this country. 



Habits — An eastern species of Hemiclepsis has been observed in 

 the living state and it is probable that the habits of the form described 

 will not depart much from this. The most striking peculiarity is its 

 remarkable activity. No other members of the family creep with 

 anything approaching its speed. In creeping the caudal sucker is 

 brought forward into actual contact with the oral sucker and the move- 

 ment is repeated with great rapidity. So far as has been observed the 

 species is entirely sanguivorous, the blood of frogs being taken while 

 worms and snails are refused. The European H. tessellata is known to 

 attack water fowl and to be transported while attached to their legs or 

 within the nasal chamber which it occasionally enters. Fertilization 

 takes place by means of spermatophores attached to the skin, but egg 

 laying has not been observed. 



Family Ichthyobdellidae. 



Leeches of small, medium or large size. Form much varied ; 

 short and stout or elongated and slender, terete or depressed, usually 

 more or less divided into a narrower anterior and an expanded pos- 

 terior region. No distinct clitellum, but diffuse clitellar glands abun- 

 dant. Segments smooth, or more rarely papillated, often provided 

 with lateral pulsating vesicles or gills on a certain number of segments. 

 Complete somites with from 2 to 14 annuli,, greatly varied in pro- 

 portions. Both, oral and caudal suckers usually large and deep and 

 more or less prominently set off on pedicles. Eyes 1 to 3 pairs widely 

 separated on posterior part of head, often absent. Eye spots often 

 on caudal sucker. Mouth and proboscis as in Glossiphonidcc ; stomach 

 straight and usually simple, only rarely with lateral cceca, one pair of 

 large posterior gastric cseca, variously and sometimes completely 

 united. Genital orifices much varied in position according to the num- 

 ber of rings per segment. Testes usually five or six pairs, the sperm 

 ducts relatively short, the epididymis and ejaculatory duct not much 

 convoluted, ending in an atrium that may be simple or more or less 

 complex; no filiform penis. Ovisacs paired or united into one, pyri- 

 form or globular, their ducts simple. Eggs laid in usually stalked 



