196 MR. F. E. BEDDARD ON [Jime 17, 



developed in one individual which was not fully mature (text- 

 fig. 49). 



The internal anatomy of the genus Poly tor ei(,tus appears, so far 

 as present observations go, to ojEfer but little variation in the 

 characters of the alimentary canal and the vascular system. I 

 find that up to the xiith segment the structure of the present 

 species is quite like that of its nearest ally. The sperm-sacs, 

 nlDreover, are constituted upon exactly the same plan. In two 

 specimens, one of the present species and one of P. kenyaensis, 

 which I divided longitudinally and placed side hj side for com- 

 parison, the dilated terminal region of the sperm-sacs reached 

 back to precisely the same segment, i. e. the xxxviiith. There is, 

 however, naturally some variation in the extent of these sacs. 



The spermiducal glands of the present sj^ecies ai'e relatively 

 larger than those of Poly tor eAitus kenyaensis ; othei-wise their 

 contoui-s are much the same. They do not, however, open directly 

 into a bursa propulsoria as in that species. The gland ends, in 

 fact, in a duct of rather naiTOwer calibre ; the ducts appear to 

 join, and in any case the bursa propulsoiia is insignificant in its 

 dimensions. That this would prove to be the case, is really 

 indicated by the external characters; the, comparatively speaking, 

 inconspicuous male pore does not suggest a large muscular ter- 

 minal sac such as is suggested by and co-exists with the wide and 

 broad external male pore of P. kenyaensis. The two drawings 

 exhibited herewith (text-figs. 50, 51, p. 198) show accurately the 

 relative dimensions of the bursa propulsoria in the two species. 

 That of Polytoreutus kenydensis is fully twice the size of that of the 

 present species. These diffei-ences are of specific value ; they have 

 nothing to do with relative matuiity. In both cases, a number of 

 segments following the median generative pores have a much 

 thickened body-wall. The ventral region of integument thus 

 increased in thickness corresponds to the genital area dealt with 

 in describing the external characters of the two species. The 

 drawing (text-fig. 50, A, p. 198) shows the pie-eminently glandular 

 nature of this area in P. montis-kenyce, where contorted whitish 

 masses of glandular substance have largely invaded the thickness of 

 the integument. It may be finally pointed out that the external 

 orifice and the lumen of the bursa propulsoria in P. montis-kenyce 

 looks forward ; while in P. kenyaensis the direction is at right 

 angles to the longitudinal axis of the body of the worm. The 

 most remarkable feature, however, about the male efierent 

 apparatus of this species is the existence of a small foiwardly 

 directed diverticulum of the spermiducal gland. This diverti- 

 culum has exactly the same appearance as the main gland, but is 

 of less calibre : it receives the sperm-duct at its free apex. It joins 

 the main gland just where the latter passes into its duct. This 

 structure is not, however, new to the genus. Dr. Michaelsen has 

 already recorded in Polytoreutus arningi ' a perfectly similar 



' "Neue u. wenig bekaiiiite afnlcanische Temcolen," J.B. Hamb. wiss. Anst. xiv. 



