138 Transactions. — Zoology. 



cular, with thick walls ; it occupies segment 5. (I find the 

 best way of locating the position of this organ is by slicing the 

 worm in two by a horizontal cut, for by the ordinary method of 

 dissection the septa are torn, especially when they are infundi- 

 buliform.) The oesophagus is narrow; it is slightly dilated 

 in 13, 14, and 15 to form rather globular diverticula, with 

 feeble lamellae internally ; in segments 16 and 17 it widens 

 out, but retains the lamellate structure of its wall, These 

 gradually die out and the intestine commences in segment 20 ; 

 it is wide, unconstricted, and differs structurally from the 

 oesophagus. 



Reproductive Organs. —There are the usual two pairs of 

 testes in 10 and 11, and two pairs of lobulate sperm-sacs in 

 the 11th and 12th segments. The spermiducal gland is a 

 thick irregularly cylindrical tube of some length, coiled some- 

 what, though not to so great an extent as in the Japanese 

 species. The coils lie in a plane, are compressed and com- 

 pacted to form what looks like a flattish lobed mass, till 

 carefully unravelled. The gland occupies only segments 18' 

 and 19 in the specimens examined. The muscular duct is 

 very short and narrow, hidden below the glandular mass, 

 which has to be lifted and turned aside ; but then it is quite 

 distinct. This duct is not bent upon itself as in the Japanese 

 species, but is transversely disposed, and passes almost 

 straight to the pore. Sections demonstrate that the sperm- 

 duct opens into the duct of the gland at the junction of the 

 gland with the muscular duct, not at the free end, as in the 

 Japanese species. Serial transverse sections are quite clear 

 on the point. The sperm-duct leaves the body-wall, crosses 

 the lower end of the gland immediately above its duct, bends 

 down towards the latter, and opens into it just at the junction 

 of the two. This can be followed out in the course of ten 

 sections. The spermathecae are in two pairs, lying in seg- 

 ments 8 and 9. Each consists of a globular sac, opening to 

 the exterior by a narrow duct, which is longer than the sac 

 itself. Each has a diverticulum (opening into the duct close 

 to the body-wall), which is only about half as long as the duct 

 and sac together. The ovaries are of considerable size, ex- 

 tending across the 13th segment. 



Affinities, &c. — In a recent article Michaelsen (p. 220) has 

 discussed the relations of the species of Pontodrilus occurring 

 on the shores of the Pacific, viz. : P. michaclseni, Eisen, Cali- 

 fornia; P. ejjhijxpiger, Eosa (p. 281), from Christmas Island; and 

 P. matsushimensis , Jizuka, Japan. He recognises the affinity 

 of the two last, both presenting a distinct "tuberculum puber- 

 tals " on the intersegmental groove 19/20, while differing in 

 details. He further describes, briefly, a single somewhat 

 damaged individual from Te One, in the Chatham Islands, 



