THE LEECHES (HIRUDINEA) 



655 



30 (29) Complete somites of six unequal annuli; salivary glands diffuse; 



gastric ceca seven pairs; caudal sucker with marginal circle 

 of glands and papillae; eyes one pair, united; size small. 

 Probably fish parasites. . Actinobdella Moore 1901 . . 31 



31 (32) Sucker papillae and glands about 60; five series of dorsal papillae. 



Actinobdella annectens Moore 1901. 



Sucker papillae and glands about 30; median dorsal series of pa- 

 pillae alone developed. 



Actinobdella inequiannulata Moore 1905. 



FIG. iooi. Actinobdella inequian- 

 nulata. Annulation, sensillae 

 and dorsal cutaneous papillae of 

 anterior twelve somites. Pos- 

 terior end with sucker from the 

 side. X 20. (After Moore.) 



33 (2) Body divided into a narrow anterior and a wider posterior region; 



little depressed; eyes when present usually well separated; 

 stomach usually with only a posterior pair of more or less 

 coalesced ceca. . . . Family ICHTHYOBDELLIDAE . . 34 



34 (35) Complete somites of 12-14 very short annuli; no distinct lateral 



vesicles; eyes one or two pairs; size small. Parasitic on 

 small fishes Piscicola punctata (Verrill) 1871. 



35 (34) Complete somites of six annuli; strongly divided into two regions; 



lateral pulsating vesicles in somites XII to XXIII; eyes 

 two pairs; size medium. Parasitic on Fundulus in fresh and 

 salt water. . , . Trachelobdetta vivida (Verrill) 1872. 



The anterior region is formed of eleven somites of which the first 

 five comprise the head and the last three the clitellum, which is 

 somewhat sunken into the widened posterior region. A little known 

 leech which has been taken only in southern New England. 



FIG. 1002. Trachelobdella-vivida. Annulation from dorsum. Somites at the 

 ends of the body are numbered and the annuli between which the male 

 and female orifices lie are indicated. X 3. (After Moore.) 



