352 PKOP. OWEN ON THE CHARACTERS [Apr. 20, 



18. ^THERiA ELLiPTiCA, Lamarck, Annales du Mus. 1808, 

 vol. X. pi. 29 and pi. 31. f. 1 ; Blainville, Malacol. pi. 70 bis, f. 2; 

 Sowerby, Conch. Icon. f. 1 a, h. 



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, 1 «. Achat ina {Limicolaria) martensiana, p. 345. 



2. ( ) rectistrigaia, p. 346. 



3. BwUmtis {Buliminus) pfychaxis, p. 346. 



4. Ennea lata, p. 347. 



4 a. Ditto (young state), p. 347. 



5. Ennea wjijiensis, p. 347. 



6, 6 a, 6 b. Tiphobia korei, p. 348. 



7, 7 a, 7 b, 1c. lieothauma tanganyicense, p. 349. 



8, 8 a. Spatha tanganyivensis, p. 350. 



9, 9 a. Unio tanganyicensis, p. 35L 



5. On the External and Structural Characters of tlie Male 

 Spirula australis, Lam. By Prof. Owen^ C.B.j F.R.S.^ 



F.Z.S., &c. 



[Eeceived April 7, 1880.] 



(Plate XXXII.) 



The subject of the present observations* is rather larger than the 

 female specimen of S])irula australis, described and figured in the 

 •Annals and Magazine of Natural History,' series 5, vol. iii. p. 1, 

 pi. i. fig. 1 (1879), and in the 'Proceedings of the Zoological 

 Society,' 1878, p. 964, pi. Ix. fig. 4. 



The body-envelope, or mantle, has the same thickness and mus- 

 cular 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 suc- 

 torial cavity ; e, its central pore ; / the ventral portion, g the dorsal 

 portion, of shell — both which are naturally exposed, but are imme- 

 diately invested by the shell-membrane, capsule, or sheath ^. 



The surface of the mantle is smooth, without trace of the reticular 

 markings characteristic of that of Spirula reticulata^. The an- 

 terior border of the mantle sends forward the median dorsal process 

 (Plate XXXII. 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 fumiel (fig. 4,j) would project, when not retracted 

 as in the specimen (fig. 2) between the ventral processes. The in- 



^ This specimen was purchased for the British Museum with other objects 

 of Natural History, said by the vendor to have been obtained during the voyage 

 of ' La Bonite : ' the locality of the capture of the Spirula was not known to him. 



' Compare with the enlarged view, ' Annals,' &c. torn, cit., pi. i. fig. 3. 



3 ' Zoology of the Voyage of H.M.S. 'Samarang,' 4to, 1848, pi. iv. figs. 3, 9, 11. 



1 



