482 



M. SEPTANGULARIS, Mont. 



Mangelia septangularis, Brit. Moll. iii. p. 458, pi. 112. f. 6,7 ; (animal) 

 pi. T.T. f. 3. 



Animal with eight spiral turns, white in all parts, powdered 

 with more intense minute flake- white points. Mantle rather 

 thick at the edges, and produced into a fleshy branchial fold 

 that extends beyond the short canal of the shell. The head 

 is compressed, narrow, with a vertical fissure below it, from 

 which a retractile proboscis issues. The coalition of the ten- 

 tacula at their bases is not in the least impeded by any pro- 

 jection of the head ; they are short, setose, with the eyes on 

 attached thick offsets at the external points, at about two- 

 thirds of their length ; the remaining portion is very short. 

 Foot rather narrow, slightly auricled, truncate in front, mo- 

 derately long, with the termination nearly as broad behind as 

 in front, without a trace of a distinct point, though it is often 

 more or less emarginate ; it carries on the upper part a strong, 

 very elongated, oval, pale corneous operculum formed of un- 

 guiculated segments. The sinus or emargination at the upper 

 part of the aperture is very slight. 



This species is not often obtained alive at Exmouth; its 

 range of habitat is from the littoral to the coralline zone. It 

 has by some authors been deposited in Pleurotoma, on what 

 grounds can scarcely be satisfactorily explained, as the 

 emargination is almost obsolete, or less conspicuous than in 

 any other of the minor so-called Pleurotomata ; besides, as 

 has been stated, the head is perfectly flat, without a trace of 

 projection to intercept the coalition of the tentacula. We 

 consider it in every respect a varicose Murex. 



The following have not been seen by me alive : 



M. CORALLINUS, Scacchi. 

 M. corallinus, Brit. Moll. iii. p. 374, pi. 102. f. 5, 6. 



M. BARVICENSIS, Johnston. 



Trophon Barvicensis, Brit. Moll. iii. p. 442, pi. 111. f. 5, 6 ; (animal) 

 pl.S.S. f.4. 



M. CLATHRATUS, Linnaeus. 

 M. Bamffius, Auct. 



Trophon clathratus, Brit. Moll. iii. p. 436, pi. 111. f. 1, 2; (animal) 

 pi. S.S.f.3. 



