4 
A New Leech 
the posterior sucker, but held on the cork of the tube it travelled in, 
and afterwards to the side of the containing jar with its anterior sucker, 
never using the posterior sucker even when irritated into letting go 
anteriorly. 
Segmentation (consult Fig. 2). 
(a) Neck. A. Head : 
(а) Anterior sucker .. .. .. .. (?)6 segments. 
(б) A portion of the anterior sucker which is apparently post¬ 
oral, and which, though not showing external annulation, probably 
represents morphologically the three small rings in a similar position 
in Calliobdella lophii .. .. .. .. .. (?)3 segments. 
B. Preclitellum .. .. .. .. .. 3 segments. 
Fig. 2. Ganymedes cratere in ventral aspect, showing segmentations and animlations. 
Numbering and lettering explained in the text. 
The clitellum is divided from the preclitellum by a deep furrow which 
shows as a very marked line in a preparation cleared in creosote, viewed 
under the microscope as a transparent object. 
C. Clitellum .. .. .. .. .. 3 segments. 
The cUtellum exactly resembles that of Calliobdella lophii. The first 
two segments are large, the second being the larger of the two, and 
neither is divided by furrows into annuli. The ^ genital aperture is 
