318 



cent and Spencer Gulfs." It is most probable Mr. Angas 

 was responsible for the identification of the examples from 

 which Professor Tate named the specimens in his cabinet. 

 There can be little doubt, therefore, that Mr. Angas and 

 Professor Tate regarded as M . vincentina, Crosse, both the 

 forms which Mr. Sowerby has described as alucinans. 



An examination of the type and cotypes received from 

 Mr. Sowerby, as well as many fresh dredged and beach speci- 

 mens since obtained, lead to the conclusion that M. alucinans, 

 Sowerby, is conspecific with M. vincentina, Crosse, and may 

 be retained to indicate a variant in which the ribs are 

 rounder and more solid, and the spiral lir» are finer and 

 more crowded. 



The species is very variable. With the same number of 

 whorls some adults may be twice as long as others, and when 

 of equal length may differ much in breadth and greatly in 

 solidity. There may be only twelve prominent spirals over 

 the body- whorl from the angulation to the notch, and be- 

 tween each of these there may be as many as twenty crowded 

 striae, or only six. Sometimes there are twenty equal promi- 

 nent threads, with fewer threadlets intervening. The striae 

 between the primary spirals may be all of equal size, or of 

 three distinct sizes; secondary ones in the middle of the 

 spaces, tertiary between them, and very fine between these. 

 In some cases the primaries may be not marked, and in others 

 absent, the spirals being all equal or nearly so. Nearly all 

 these differences may be found among the cotypes themselves. 



As to colour markings, the boldest, most frequent, and 

 persistent is the spiral row above the angle, with the trans- 

 verse spots in the intercostal spaces. Next one in the middle 

 of the body-whorl, then one between this and the snout, 

 then one between the latter two, and then one between the 

 former two. All these below the angle are on the ribs, and 

 interrupted by the spaces, except in a very few examples, 

 when they form a continuous spiral line, distinctly thinner 

 in the interspaces. Rarely some individuals are also min- 

 ut-ely dotted with brown all over the whorls, but most abun- 

 dantly just below the sutures, and the intercostal spaces be- 

 low the lowest spiral may have short-curved axial brown 

 flames. 



Dredged alive in Gulf St. Vincent from 5 to 22 fathoms, 

 many alive ; in 15 to 35 fathoms St. Francis Island, seve- 

 ral ; in 45 fathoms off Neptune Islands, 4 fresh ; in 55 fath- 

 oms off Cape Borda, 19 moderate: in 62 fathoms, 11 moder- 

 ate; in 90 fathoms off Cape Jaffa, 1 poor; and in 110 fath- 

 oms off Beachport, 1 poor. Taken on the beach as far west 



