77 



lobed orifice as in Trocheta. The internal male organs resemble 

 those of Aulastomum and Hirudo, the testicles being rather largc 

 i'ounded or pyriforme vesicles, appcarently but eleveu on each sidc. 



Hexabdella n. gen. unterscheidet sich von Semiscolex durch 

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

 ihrer Augen. Body depressed j)Osteriorly. Cephalic lobe prolon- 

 gated, composcd of four segments, with threc longitudinal folds be- 

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

 these the Oesophagus is furnished with six longitudinal plications. 

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

 second segnaent behind the buccal. Anus doi'sal, at the posterior 

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

 a deep constriction. 



Macrobdella erinnert an Aulastomum^ Hirudo, Haemopis, 

 unterscheidet sich von denselben aber folgendermaassen : Body 

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

 little. Cephalic lobe large, i-ounded in front, composed of five Seg- 

 ments, its lower surface rugose with longitudinal sxücations and at 

 the base haviug 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 jplications within the Oesophagus. Stomach voluminous, dividod 

 into several compartments, with very largo 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 opeuing dorsal, in advance of the posterior sucker. 



Weiter gehören hieher: Nephelis fervida und loh- 

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

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



Ebenso handelt Leidy über Hirudo decora Say, 

 den gewöhnlichen (medicinischen) BlutegelNord- Amerika' s, 

 und Aulastomum lacustris n. vom 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. 



Trematolles. 



Grimm erwähnt in seinen „Beiträgen zur Fauna 

 des Gouvernements von St. Petersburg" (Verhandl. der 

 Petersburger Gesellsch. der Naturforscher T. H. p. 84 — 

 111) des Vorkommens von sechs Trematodcn aus den 



