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Show 352 PROF. OWEN ON THE CHARACTERS [Apr. 20, 18. ^ETHERIA ELLIPTICA, Lamarck, Annales du Mus. 1808, vol. x. pl. 29 and pl. 31. f. 1 ; Blainville, Malacol. pl. 70 bis, f. 2; Sowerby, Conch. Icon. i. 1 a, b. A single old thick dead specimen forms part of the collection. In addition to the preceding, the collection contains a species of Perideris, but too immature for identification, a third species of Ennea, and a Physa, both being in a very decayed state. EXPLANATION OF PLATE XXXI. Fig. 1, la. Achatina (Limicolaria) martensiana, p. 345. 2. ( ) rectistrigata, p. 346. 3. Bulimus (Buliminus) ptychaxis, p. 346. 4. Ennea lata, p. 347. 4 a. Ditto (young state), p. 347. 5. Ennea ujijiensis, p. 347. 6, 6 a, 6 b. Tiphobia horei, p. 348. 7,7a, 7b, 7c. Neothauma tanganyicense, p. 349. 8, 8 a. Spatha tanganyicensis, p. 350. 9, 9 a. Unio tanganyicensis, p. 351. 5. On the External and Structural Characters of the Male Spirula australis, L a m . B y Prof. O W E N , C.B., F.R.S., F.Z.S., & c [Received April 7, 1880.] (Plate XXXII.) The subject of the present observations1 is rather larger than the female specimen of Spirula australis, described and figured in the 'Annals and Magazine of Natural History,' series 5, vol. iii. p. 1, pl. i. fig. 1 (1879), and in the 'Proceedings of the Zoological Society,' 1878, p. 964, pl. Ix. fig. 4. The body-envelope, or mantle, has the same thickness and muscular development: its terminal modifications for attachment are closely repeated; they are represented of the natural size in Plate XXXII. fig. 3, in which are shown :-a, a, the terminal pallial lobes ; b, the fleshy cushion ; c, c, the rudimental or quasi fins ; d, the suctorial cavity ; e, its central pore ; / the ventral portion, g the dorsal portion, of shell-both which are naturally exposed, but are immediately invested by the shell-membrane, capsule, or sheath2. The surface of the mantle is smooth, without trace of the reticular markings characteristic of that of Spirula reticulata3. The anterior border of the mantle sends forward the median dorsal process (Plate X X X I I . fig. 1, h) and the pair of ventral sublateral processes (ib. fig. 2, i, i) : the former is the longer and larger; and all terminate obtusely. The funnel (fig. 4, j) would project, when not retracted as in the specimen (fig. 2) between the ventral processes. The in- 1 Tbis specimen was purchased for the British Museum with other objects of Natural History, said by the vendor to bave been obtained during the voyage of ' La Bonite:' the locality of the capture of the Spiirula was not known to him. 5 Compare with the enlarged view, ' Annals,' &c. torn, cit., pl. i. fig. 3. 3 ' Zoology of the Voyage of H.M.S. 'Samarang,' 4to, 1848, pl. iv. figs. 3,9, 11. |