170 RISEN. [Vol. II. 



Dorsal vessel alternately double and single from vii backwards. 

 Hearts x-xii. Ncphridia, meganephridia, most anterior one 

 in iii. Testes x, xi. Sj^enn funnels x, xi. Sperm duets join 

 only at the pore. Sperm sacs in ix pre-septal, in xii post- 

 septal. Prostates long, slender, tubular, abruptly bent at the 

 pore, sometimes extending over more than one somite. Spej'- 

 mat/iecae, three pairs in vii-ix, club-like, with an ear-shaped 

 diverticle below the center. 



Habitat. — Illinois, in black prairie soil. 



DiPLOCARDIA SINGULARIS UdE. 



Definition. — Color, flesh. Size, 65 mm. by 3 mm. Prosto- 

 miufn divides somite i about one-half. Dorsal pores, most an- 

 terior one vii/viii. Spermiducal pores xix. SpermatJiecal pores, 

 three pairs, vi/vii, vii/viii, viii/ix. Prostate pores xviii, xx. 

 Oviducal pore xiv, interior to setae a, surrounded by a glandu- 

 lar ridge. Setae, ventral, lateral, d-d greater than half the 

 periphery ; a-a larger than b-c ; c-d somewhat larger than a- 

 b; a-b about one-half as large as b-c ; l.i. shorter than v.i.\ 

 a-b twice shorter than l.i. and three times shorter than v.i.; 

 faintly ornamented at apex. No setae a-b in xix. Penial 

 setae three times longer than the ordinary setae, curved, not 

 ornamented. SpermatJiecal setae not differentiated. Clitelhmi, 

 ring-like xXxx-Y-z xvii, saddle-shaped Yi xvii-xviii. Genital zone, 

 no rectangular field, two lunate grooves on Yz xviii-)-^ xx, con- 

 vexity towards ventral median line. One pair papillae in xvii. 

 One pair in xx. Sometimes with a deep oval zone in xvii- 

 Y xxi (Smith's specimens). OesophagJis strongly twisted, bead- 

 like in x-xiii, narrower in xiv-xvi, no calciferous folds. Giz- 

 zards V, vi. Sacculated intestine commences in xvii. Dorsal 

 vessel single. Hearts, three pairs in x-xii ; in iv-ix narrow 

 vessels. Meganephridia, pores ventral to setae d. Testes x, 

 xi. Sperm funnels x, xi. Sperm sacs, one pair in ix pre-septal, 

 one pair in xii post-septal. Prostates with many folds at right 

 angles. SpermatJiccae, three pairs in vii-ix, sac-like, with grad- 

 ually narrowing duct, with oblong diverticle. 



Habitat. — Danville and Havana, Illinois. 



