MUKEX. 495 



is the " rugged form " of the M . nebula of the ' Brit. Moll.' 

 vol. iii. p. 477 : fig. 7. of pi. 114 is this form and our M. 

 Ginannianus. 



I might have generalized in this species, but I am obliged 

 to give a somewhat more detailed account of it than usual, 

 as it is the standard of comparison with the two next spe- 

 cies, with which it has been considered identical by some 

 conchologists. 



I have myself dredged this species in the laminarian 

 zone off Budleigh Salterton. A larger variety is taken occa- 

 sionally in the deeper waters of the coralline zone, which I 

 am inclined to think may turn out a distinct species. It 

 appears in ' Brit. Moll/ vol. iii. p. 478, as var. pyramidata of 

 Mangelia nebula. The organe generateur is precisely similar 

 to that of Murex gracilis. 



M. NEBULA, Montagu. 



Mangelia nebula, Brit. Moll. iii. p. 476, pi. 114. f. 7, 8, 9; (animal) 

 pi. R.R. f. /. 



This animal has the closest alliance with M. Ginannianus, 

 therefore only the very doubtful and almost inappreciable 

 variations will be mentioned. In this species the eyes appear 

 larger and the tentacula proportionately shorter than in 

 M. Ginannianus. The general aspect of the shells of the two 

 species appears to afford even better specific distinctions than 

 the animals. In August 1849, I dredged in Littleham Cove, 

 near Exmouth, in the laminarian zone, several specimens 

 both of the M. Ginannianus and M. nebula at the same 

 haul; they proved lively and afforded a good examination 

 for some hours; and the differences between them with 

 respect to the shells are, that the M. Ginannianus is less 

 slender, the aperture more patulous, and the colour of 

 a uniform yellow, whilst that of M. nebula is much darker, 

 and shows a still darker spiral band in the sutures. The 

 animals also differ : the M. Ginannianus has the ground 

 colour of a very pale yellow-brown, suffused with a tinge of 

 light red, and the flakes with which the whole body is aspersed 

 have a light sulphur tinge ; whereas in M . nebula the ground 



