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Show 1887.] PROF. F. J. BELL ON HOLOTHUROIDS. 531 its use may be it is impossible to state at present, but that some important part in the economy of the Marsupial can hardly be doubted. The appearance of the patch of integument is not unlike that figured by Garrod ] in Dorcopsis luctuosa, but its position is very different in the two forms. With this possible exception I am not able to compare the glandular patch of Myrmecobius to any structure in any other Marsupial; the result of the present paper therefore must be the addition of a new character to the diagnosis of Myrmecobius. 3. Studies in the Holothuroidea.-VI. Descriptions of new Species. By F. JEFFREY B E L L , M.A., Sec. R.M.S., Professor of Comparative Anatomy and Zoology in King's College2. [Received June 21, 1887.] (Plate XLV.) During the somewhat protracted period in which I have been engaged in determining the large collection of Holothurians in the British Museum, I have noticed a few species of no interest sufficient to justify immediate description, but which, being as yet undescribed, may (on the completion of my work) have their characteristics published. The date on which this paper is read will explain why some of the specie3 are named as they are. CUCUMARIA SANCTI-JOHANNIS, sp. nov. (Plate XLV. fig. 1.) Body considerably elongated; suckers highly retractile, confined to ambulacra and arranged in irregular double rows; no anal teeth. Calcareous oesophageal ring greatly reduced, the radial piece small, slightly notched posteriorly, completely covered by the insertion of the retractor muscle ; the interradial piece a fine filament. The retractors of extraordinary length, extending along two thirds of the whole length of the body, with a broad belly of insertion and long tendon-like band of origin. Stone-canal and several Polian vesicles long. The genital tubes long, simple, and numerous; the Cuvierian organs are apparently wanting. The spicules (Plate XLV. fig. 1) are numerous and exceedingly simple ; at the narrow end there is a tendency to produce a spine ; spicules of various stages are shown in the figure. Two specimens, measuring 50 and 95 millim. respectively, appear each to have a greatest width of about 13 millim. Ojica, Goto Islands. Collected by Capt. St. John, R.N., H.M.S. • Sylvia.' This species is really remarkable ; not only for the reduction of the oesophageal ring, which, it may be remembered, is quite aborted in 1 P. Z. S. 1875, p. 48, pl. viii. 2 P. Z. S. 1884, p. 563. |
