186 A. EB Verrill—North American Fresh-water Leeches. 
the others. Male aperture in the 24th annulus; female orifice 4 
in the 29th. (Esophagus capacious, with twelve folds. “Jaws 7 
thin, small, when at rest included in pouches formed by am — 
eversion of the mucus membrane. Teeth 12 in numberto Ff 
each jaw, bilobed at base.” Color throughout ve “ 
closely maculated everywhere with confluent spots of a darker | 
hue of the same color. A variety was lighter green with — 
fewer spots of blac 13 
Twin Lake, Minnesota, and Lake Superior,—Leidy. 
SEMISCOLEX Kinberg. pie: 
Ofversigt af Kongl. Vet. Akad. Férhandlingar, xxiii, p. 357, 1867. e 
According to Kinberg this genus has the following chara 
ters: maxille wanting; pharnyx with a transverse suleus he 
low the posterior margin of the buccal segment, and below that 
provided with longitudinal sulci; habit of Hirudo. 
Semiscolex juvenilis Kinb., loc. cit. 
_The following species, although evidently allied to Semiseoleh ae 
differs decidedly in the structure of the cephalic lobe ie ; 
pharynx, and in having ten ocelli. These characters seem om 
of generic value. 
HEXABDELLA, gen. nov. 
terior : 
rat of 
ngth, in partial contraction, 1°50 inches ; breadth 40. a 
or cephalic lobe, somewhat elongated, rounded in front, font 
four annulations, the first or terminal one oval, remite he 
: 
dy strongly annulated, broad and much flattened 
