189 



On Some Nev^ Species of Australian 

 Marine Gastropoda. 



By Professor Ralph Tatp:. 



Plate I. 



[Read June 6, 1893.] 



Sipho (?) mimetieus, ^pec. nov. Pi. L, fig. lo. 



Shell pyriform, imperforate, uniformly sordid-white, whorls 

 four and a-half, suture distinct but not canaliculate ; embryo of 

 one and a-half turns, naticiform, smooth ; first spire-whorl and 

 anterior-half of second angulated medially ; the rest angulated 

 over the suture, flatly-convex behind, with five revolving threads 

 at the posterior suture a double thread which is slightly cren- 

 ulated by oblique slender costie fading-off anteriorly into threads. 



Body-whorl ventricose in front of the periphery, periphery 

 ornamented with subacute nodulose crenatures (about twelve), 

 posterior area slightly concave with five raised threads finely and 

 closely elevate-striated in the intervals, at the suture a thickened 

 lira which is slightly crenulated ; anterior part of body-whorl 

 with raised threads, wdiich are more or less equal and equi- 

 distant. 



Aperture rhomboid-oval ; outer lip smooth within ; columella 

 covered with a thin callus, regularly concave ; the base is 

 gradually contracted into a moderately-elongated snout, nearly as 

 long as the aperture, bent to the left and slightly upturned. 



Dimensions. — Total length, 15-5; greatest diameter, 8-5; length 

 of aperture, 12 ; width of aperture, 4. 



TIahitat. — Dredged by Mr. E. H. Matthews, on December 31, 

 1888, from a sandy bottom on Tapley's Shoal, about eight miles 

 off Edithburgh, in 12 to 16 fathoms (one dead specimen). 



Affinity.— This shell is probably immature and its generic 

 loccition is uncertain. It has a general resemblance to Fulyur 

 cancdiculatus, Linn., from the young of which it is separable by 

 its more ventricose body-whorl, shorter and more tortuous snout, 

 and generically by the absence of a columella -fold. It bears a 

 resemblance to some species of Sycum, though the form of the 

 embryo and the smooth test in that genus prohibit its attach- 

 ment thereto. It is also like Streptosiphon 2>orphyrostoma, which 

 has, however, an oblique double fold on the columella. 



Taking separately the conchological characters of this shell 



