| OCR Text |
Show 332 DR. W. B» BENHAM OX [Nov. 15, «xamination of the surface, owing to the strongly contracted state of the worm : the nephridiopores, however, are in line c. Text-fig. 48. JtJiododrilus edulis.- Ventral view (X about 3) of clitellar region, showing male pores ( $ ) and arrangement of tubercula pubertatis (T .P .) ; A B [a b in the text], the chaetal rows. Segment 16 is unfortunately drawn a little too large. Internal Anatomy. The body-wall is of great thickness and the septa behind segments 7 to 12 are very stout. The dorsal vessel is single ; the last heart in segment 13, and rather smaller ones in 10, 11, and 12. The gizzard, in segment 5, is large, with thick walls, and contains stones. There is no oesophageal gland, nor any dilatation. The intestine commences in the 17tli segment, where the gut suddenly enlarges to twice its previous diameter. The worm is meganephric, and the nephridia commence as far foi'wards as segment 3. Each nephridium (text-fig. 49) consists of a bunch of 3-5 loops ventrally (situated in line a-b), whence a long dorsal loop passes upwards to a point about midway between c d, and a straight duct leaves the same bunch, and passes to the body-wall just below c, at which point no doubt it opens externally. There is, in addition, a blind caecum or bladder with muscular wall, which extends almost to the mid-dorsal line : the exact connections of it I have not determined. The nephridiostome is small. |
