ENCHYTR^ID^ 



47 



For want of specimens of M. grandls this relationship cannot now 

 be cleared up. It may be possible that M. grandis is identical with 

 M. harritnani^ the spermathecaj having become accidentally reduced. 



MESENCHYTR^US FUSCUS sp. nov. 

 p1. VIII, figs. 3-5; text-figs. 21-23. 



Definition. — Length 15 mm., width i mm. Somites 58. Setae 

 sigmoid : laterals, 3, 3, 3, 3, 4 ; postclitellars 3, 3, 4, 4, 4 ; ventrals, 6, 

 6? 7? Iih^'i postclitellars, 6, 6, 6, 5 (5, 3, 2). Head-pore large, near 

 the apex. Clitellum, dorsally XI-XIII, ventrally -^ XI-XIII. Copula- 

 tory papilla of medium size. Intestine in II and III much narrower than 

 in the following somites. Septal glands in somites III-VI. Brain 

 posteriorly truncate, anteriorly deeply incised. Dorsal vessel rises in 

 somite XX 

 and at once 

 is very thick. 

 Spermatheca 

 with two saus- 

 age-shaped di- 

 verticles nearer 

 the pore than 

 the intestine. 

 The diverticles 

 are about one- 

 third as long 

 as the whole 

 spermatheca. 

 Sperm-ducts 

 about twelve 

 times as long 

 as the funnel, 

 extending back 

 some nine so- 

 mites, or to XXI. Funnels very large, helix-shaped. An atrial 

 chamber into which open independently of each other six to eight glands. 

 Penial glands opening at the base of the sperm-ducts. Sperm -sacs very 

 large, one pair extending as far back as somite XXVII or further. One 

 ovisac. Nephridia with two almost circular lobes. Lymphocytes 

 few, flat and circular. 



Locality. — In moss in Pit River (below the falls) , California. 

 Also from several other localities in northern California. Collected 

 by Dr. Richard C. McGregor. 



Fig. 21. Mesenchytrceus fuscus. 



