der niederen Thiere während der J. 1870 u. 1871. 441 



lobed orifice as in Trocheta. The internal male Organa resemble 

 those of Aulastomum and Hirudo, the testicles being rather large 

 rounded or pyri forme vesicles, appearently bat elevon on cach side. 



Hex ab de IIa n. gen. unterscheidet sich von Semiscolex durch 

 die Bildung des Kopfes und Pharynx, so wie durch die Zehnzahl 

 ihrer Augen. Body deprcssed posteriorly. Cephalic lobe prolon- 

 gated, composed of four segments, with three longitudinal folds be- 

 neath, followed by three transverse fleshy lobes or folds; below 

 these the Oesophagus is furnished with six longitudinal plications. 

 Ocelli ten; the fourth pair on the buccal segment, the fifth on the 

 second segment behind the buccal. Anus dorsal, at the posterior 

 end of the body. Acetabulum round, separated from the body by 

 a deep constriction. 



Macrobdella erinnert an Aulastomum, Hirudo, Haemopis, 

 unterscheidet sich von denselben aber folgeüdermaassen : Body 

 strongly annulatecl, stout, broad, depressed throughout, tapering but 

 little. Cephalic lobe large, rounded in front, composed of five seg- 

 ments, its lower surface rugose with longitudinal sulcations and at 

 the base having a transverse fold, which forms sockets for the pro- 

 tection of the maxillae, when retracted. Maxillae three, stout and 

 prominent, the outer edge denticulated, with about 50 to 60 teeths. 

 Nine plications within the Oesophagus. Stomach voluminous, divided 

 iuto several compartments, with very large and irregulär dilations 

 or pouches on each side. Ocelli ten. Male orifice between the 26th. 

 and 27th. segments, behind the mouth; vulva between the 31th. 

 und 32th. Anal opening dorsal, in advance of the posterior sucker. 



Weiter gehören hieher: Nepheiis fervida und Ich- 

 thyobdella punctata nn. sp. aus dem Oberen See, Smith 

 and V er rill cbendas. Vol. IL p. 448. 



Ebenso handelt Leidy über Hirudo decora Say, 

 den gewöhnlichen (medicinischen) Blutegel Nord Amerika's, 

 und Aulastomum lacustris n. vorn Oberen See, eine Form, 

 die nach ihrer Färbung leicht für eine Varietät des Eu- 

 ropäischen Hirudo medicinalis gehalten werden könnte. 

 Proceed. Acad. nat. bist. Philadelphia 1868. p. 229. 



Trematodes. 



Grimm erwähnt in seinen „Beiträgen zur Fauna 

 des Gouvernements von St. Petersburg" (Verhandl. der 

 Petersburger Gcsellsch. der Naturforscher T. II. p. 84 — 

 111) des Vorkommens von sechs Trematoden aus den 



