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Show 160 MR. F. E. BEDDARD ON W O R M S [Feb. 16, hoped would be more thorough, were cut short by the drying up of the specimens ; I had proposed to study the vascular system in detail, but m y failure to do so is the less to be regretted since Prof. A. G. Bourne has recently published 1 an excellent account of the circulatory organs of the large Megascolex cceruleus, which would probably in any case have rendered a similar account of the circulatory organs of Perichceta unnecessary. I may, however, call attention to figs. 7 & 8, which represent a portion of the capillary network upon the spermathecal diverticulum drawn from the living organ. It will be noticed that this network is of some vertical thickness ; its branches lie in two planes, both of which are contained in the superficial layers of the pouch and do not penetrate between the cells of its lining epithelium. The atrium is not furnished with a terminal sac. A crowd of closely pressed white egg-shaped glands corresponds to each of the genital papillae (Plate X. fig. 2). The setce of segments vi., vii., viii., ix. are longer and stouter than those upon the anterior and posterior segments ; this is especially the case with the more laterally placed. The seta formula is as follows:- Segment I. V. XII. XXV. 28 26 42 48 PERICHCETA BERMTJDENSIS, n. sp. I received thirty or forty examples of this Perichceta preserved in spirit from the Bermudas ; I am indebted for them to Surgeon- Major Windle. The specimens were all of about the same size ; the length of one specimen chosen at random is 120 mm., breadth 4 mm., number of segments 93. The colour (in alcohol) is a reddish brown dorsally, passing into a yellowish colour ventrally. The prostomium extends back over about half of the peristomial segment. The setce are small on the first setigerous segment; they gradually increase in size on the next three, and then get small again ; they are quite small on segment ix. They form complete circles. The clitellum shows the unusual, though not unique (see description of Perichceta dyeri, p. 157), character of not completely occupying three segments. Instead of being developed over the entire circumference of segments xiv.-xvi., it only commences to be visible 1 m m . after the boundary-line of segments xiii./xiv. and terminates at about the same distance in front of the boundary-line between segments xvi./xvii. This gives the clitellum a peculiar and very characteristic appearance. As it occurred in all the specimens which I examined, I regard this reduction of the clitellum as a valid specific character. The clitellum is not entirely unprovided with setae ; there is a 1 "On Megascolex cceruleus, Ternpleton, from Ceylon, &c," Q. J. Micr. Sci. vol. xxxii. p. 49. |