DESCRIPTIONS OF EARTHWORMS. 233 



intersegmental groove between segment 7 and 8 , but about 

 from the middle of the 7th segment. The 8th septum is 

 absent and the 9th one, instead of being inserted at the 

 boundary of segment 9 and 10, originates from the middle 

 of the ninth segment. The septa 10 , 11 and 12 are rather 

 thick and muscular , on the contrary the 9th one is thin 

 and membranaceous. The gizzard lies between the 7th and 

 9th septum and therefore appears to belong to the segments 

 8 and 9. The portion of the intestinal canal, occupying 

 septum 11 and 12 has a thick glandular wall, provided 

 with numerous lamellar folds; the sacculated intestine 

 commences in segment 15. In the 26th segment the intes- 

 tinal canal is provided with a pair of tubular coeca , direc- 

 ted forwards. 



The nephridia are represented by a network of small 

 tubules; in the anterior segments they occupy the total 

 internal side of the body-wall; in the succeeding segments 

 however they are confined to the vicinity of the mesenteries. 



The main stems of the vascular system consist of a dor- 

 sal, a ventral, a supra-intestinal and an infra-intestinal 

 vessel, moreover there are a pair of strong lateral vessels 

 along the ventral side of the gizzard ; the dorsal and ven- 

 tral vessel communicate by four pairs of commissural vessels 

 in segment 6 , 7,8 and 9. In the succeeding segments 

 10 — 13 large abdominal hearts are situated, which arise 

 from the supra-intestinal vessel. 



The four pairs of spermathecae occupy segment 6,7,8 

 and 9 ; as the 8th septum is absent , the two last pairs of 

 them are not separated by any mesentery. Each spermatheca 

 (fig. 2) consists of a long tubular pouch, provided with 

 several transversal, parallel grooves and of a small stalked 

 diverticulum , which reaches to the half of its length ; in 

 neither of them the presence of spermatozoa could be stated. 



The sperm-sacs are situated in segment 10, 11 and 12 

 and enclose the funnels of the vasa deferentia, Avhich termi- 

 nate in segment 18 with a horseshoe-shaped muscular duct; 

 the prostate (fig. 3) attached to it is a large lobated organ. 



Notes from tlio Leyden ]Vlus0uiii , Vol. XII. 



