OCR Text |
Show 1896.] FROM THE SANDWICH ISLANDS. 201 once open into the lumen of the duct; they become narrower and somewhat triangular in section, losing at the same time their ciliated lining. In cross-sections the two tubes are seen to lie in close contact with each other and with the lumen of the spermi-ducal- gland duct. Ultimately, just where the gland-duct perforates the body-wall on its way to the exterior, the sperm-ducts open into it. Perichseta molokaiensis, n. sp. This is a moderately small species, 81 m m . in length, and consisting of 93 segments. The prostomium is small, and is continued by grooves on to first half of first segment. The dorsal pores commence on x./xi., and are visible upon the clitellum. The clitellum has a few setae on its last segment, and extends over segments xiv.-xvi. There are no genital papillae. The male pores are separated by 15 setae. The first septum separates segments iv./v.; none are specially thickened. The intestine begins in xv.; the caeca are in xxvi., and are not large. The sperm-sacs are large, and are in xi., xii.; the sperm-reservoirs (containing the funnels) in x., xi. The spermiducal glands extend from xvii.-xxi., and are much lobed. Their duct is long and curved, but has no terminal sac. The spermathecce are four pairs in vi.-ix. The pouch is sharply marked off from the long duct. The diverticulum, ending in an oval dilatation, is about as long as the latter. Hab. Molokai. Remarks.-As I have only had a single specimen of this species at my disposal, I have been careful to injure it as little as possible. Hence m y description is in places somewhat defective. I believe, however, that this description is sufficient to avoid a confusion with allied forms. It is certainly not far from Perichceta peregrina of Fletcher1, chiefly in the large size of its spermiducal glands. Mr. Fletcher does not say how many of the clitellar segments of P. peregrina have setae, a matter which is apparently of some importance in the discrimination of species. Perichaeta hawayana, Bx)sa. The length of the largest example of this species in 150 mm.; the number of segments of that individual was 97. The colour is brown, with a pure flesh-tinge in parts. The seta-formula is as follows :- I. V. XII. XVI. XXI. 16 26 43 45 50 1 Proc. Linn. Soc. N. S. W . 1886, p. 969. |