1891.] Some Recent Papers on Earthworms. 9 
ee, Two pairs of sperm sacs; Digaster. 
yy, Clitellum on somites 14-18; sete 
in couples ; Eudrilus. 
777, Clitellum on somites 13-17 ; 
lobed prostates, one pair ; Microscolex. 
m7, Clitellum on somites 13-20; 
prostates tubular, two pairs; Dichogaster. 
PPBBPR, Male pores on somite 18. 
y, Two pairs of prostates on somites 
17-109. : 
ò, Male pores in a deep fossa ; Trigaster. 
ð, Male pores notin a fossa; Acanthodrilus. 
yy, One pair of prostates on somite 18. 
6, Clitellum on somites 13-17. 
€, Prostomium dovetailed. 
č, Prostate convolu- 
ed; Pontodrilus. 
fC, Prostate lobate; Cryptodrilus. 
ee, Prostomium not dove- 
tailed ; * Photodrilus. 
60, Clitellum on somites (13) 
14—17; prostomium dove- 
tailed; setæ separate ; Plutellus. 
066, Clitellum on somites 14-18. 
e, Setz equidistant ; Didymogaster. 
ee, Setæ in couples; Perissogaster. 
6000, Clitellum on somites d 
13—21 or more ; Megascolides. 
rrr, No prostates; clitellum on 
somites 16-21 ; Brachydrilus. 
PBBRBABB, Male pores 18-19. 
y, Prostomium broad ; sete simple; 
clitellum 15-23. Geoscolex, 
77, Prostomium elongate ; sete or- 
namented ; clitellum 15-25 ; Rhinodrilus. 
BBBBBBBS, Male pores on somite 19. 
y, Clitellum 10-25 ; Microcheta. 
