98 WILLIAM BLAXLAND BENHAM. 



of these prostates consists of two regions traversed by a lumen. 

 The distal blind extremity has a looser structure and a more 

 granular appearance, whilst the proximal portion, near the 

 external pore, has a nacreous aspect. 



The distal portion is coiled, and has a layer of columnar 

 cells (fig. 42, b) surrounding the lumen. Beyond this layer is a 

 deeper one of club-shaped gramilar cells (a), very similar to the 

 cells in the epidermis of the clitellum of Lumbricus, &c., 

 and as in that region there are capillary blood-vessels traversing 

 this glandular layer. The outer wall of this region is formed 

 by thin but firm membrane. 



The epithelium of the lumen in the proximal region (fig. 41) 

 consists of tall, narrow, columnar cells, with a highly refracting 

 cuticle, and, instead of a deep layer of granular cells, there is a 

 muscular layer, consisting of oblique fibres, as well as circular 

 and longitudinal fibres. In this region, too, the capillary blood- 

 vessels ramify amongst the epithelial cells. Outside the mus- 

 cular layer is a thin membrane, as in the glandular region. 



I could find no spermatozoa or other contents in these 

 organs. Their proximal portion is probably extrusible, and 

 represents the penial region of the duct in Perichseta, whilst 

 the slightly coiled portion will correspond to the greatly coiled, 

 compact, glandular " prostate ^^ of that genus. The external 

 pores of these " prostates'"^ lie at the base of the papillae, which 

 form the boundaries of the ventral " copulatory fossa ;" a pore 

 being at the base of each papilla. 



The two ovaries lie in somite xii (fig. 34), one on each side. 

 The ovary is a grape-like mass of lobules, and is attached to 

 the anterior septum of the somite (fig. 39). Each lobule is 

 supplied by a blood-vessel, around the branches of which are 

 set the ova, embedded in the coelomic epithelial cells (fig. 40j. 

 Each ovum has the characteristic structure. 



In each of the somites vii and viii there is a pair of sub- 

 globular white sacs (fig. 34, a, a') , opening to the exterior in 

 the posterior region of the somite, close to the nerve-cord, in a 

 line with the ventral setae (fig. 31, e, e'). When I examined these 

 sacs by teasing them I could find no spermatozoa in them^ but 



