86 WILLIAM BLAXLAND BENHAM. 



comparatively large, and lie quite freely in their somites. One 

 pair lies in somite xii, the other pair in somite xiii (fig. 17, 

 h, j). Apparently, therefore, the posterior ciliated rosette on 

 each side lies in front of its seminal reservoir. Perrier has 

 described a similar condition in Pontodrilus, and Beddard 

 for Acanthodrilus dissimilis, but in these cases the first 

 rosette is in front of the seminal reservoir. It seems to me 

 that, at any rate in Urobenus, this condition is due to the 

 immaturity of the worm; for in Lumbricus agricolathe 

 seminal reservoirs appear at first as outgrowths from the septa 

 anteriorly and posteriorly in the case of the first pair, or pos- 

 teriorly only in the case of the second pair, without any con- 

 nection between those of the two sides in the somite in which 

 the ciliated rosettes lie, so that if the worm be dissected in an 

 immature condition it would present somewhat the appearance 

 seen in Urobenus. 



Similarly, the freedom of the ciliated rosettes seems to have 

 the same explanation, since these also are free in Lumbricus 

 in the above-mentioned condition, but, as is well known, become, 

 in the fully mature worm, completely enclosed in the seminal 

 reservoirs. I have mentioned the same condition in Micro- 

 chseta Beddardi. 



A sperm-duct passes from each of the ciliated rosettes to 

 the body wall ; here it turns backwards, and the two sperm- 

 ducts on each side unite in somite xiii, and the common duct 

 thus formed runs along the body wall to somite xx, where it 

 opens to the exterior in the anterior region of the somite, 

 between the ventral and lateral couples of setse. 



There are no accessory glands on the sperm-duct, nor copu- 

 latory papillae on the exterior. 



The only female organs which I could find are the three 

 pairs of spermathecse (fig. 17, f). Each spermatheca is a 

 white, elongated, pyriform sac, the free extremity of which is 

 rounded, while the opposite extremity gradually narrows to 

 form a delicate duct ; it is bent upon itself once or twice in its 

 course, and opens to the exterior in the anterior region of the 

 somite, quite close to, but distinctly separated from, the 



