607 



MISCELLANEA. 



Note on Diastoma melanioideSf Reeve (Mesalia). 

 By Sir Joseph Verco, M.D. (Lond.), F.R.C.S. (Eng.). 



Diastoma melanioides, Reeve. 



Mesalia melanioides, Reeve, Conch. Icon., vol. v., pi. i., f. 3. 

 Hab.(?) E. A. Smith, Ann. alad Mag. Nat. Hist., Ser. 8, vol. 

 XV., 1915, p. 370. 



Mesalia exilis, Sowerbv, Ann. and Mag. Nat. Hist., vol. xii., 

 p. 236, pi. iii., fig. 9, W. Austr. 



This shell was dredged by me in 1895 in 15 fathoms off 

 Thistle Island, at the entrance to Spencer Gulf, with two 

 smaller examples, and measured 42 mm. in length and 

 ir25 mm. in breadth. A dead shell was found on the Thistle 

 Island beach. Off the Banks Group, in Spencer Gulf, in 

 12 fathoms, one small fresh example was dredged and one of 

 medium size dead. Later four specimens were taken on St. 

 Francis Island beach, the largest of which, in perfect con- 

 dition, was 41 mm. long and 12'5 mm. wide. In Petrel Bay, 

 on the north of the island, in 15-20 fathoms, five very email 

 dead specimens were dredged, and in 6 fathoms three tips. 



I In 1911, at Esperance Bay, on the south coast of Western 



I Australia, six full-grown beach specimens were obtained 

 measuring up to 42*25 mm. long by 12*75 mm. wide. Shortly 



I fifterwards one of the latter was given to Mr. G. B. Sowerby 

 when on a visit to Australia, as an example of M. melanioides, 



I Rve., from Esperance, and a little while after this a reprint 

 was received from him containing the publication of his 

 31 . exilis. "When reminded of the circumstances under which 

 he obtained it, he explained that he had failed to make a note 

 of them at the time and they had slipped his memory, and 

 without doubt his name was a synonym of M. melanioides, 

 Rve. Its type locality is Esperance Bay. 



The whorls in some examples are nearly flat and sloping, 

 in others slightly convex ; with a finely canaliculate suture, and 

 with a shallow spiral groove about one-fifth the width of the 

 whorl below the suture, which consequently seems somewhat 

 marginal or adpressed. The numerous broad rounded axial 

 costae are very valid in the upper whorls, where many of them 

 are variceal, and these may form in some examples three vertical 

 lines of varices, each just in front of that above; in other 



