120 Mr. W. Clark on the Muricidse. 



lobe without wings or caudal api)endages, on which is fixed an 

 exceeding light horn-coloured, subrotuud, corneous operculum at 

 some little distance from the termination of the pedal disk, and 

 is marked with the usual characteristic strige of increment of the 

 muricidal opercula. I can say nothing of the branchial plume 

 and reproductive organs, being unwilling to make perhaps a 

 useless attempt to see them by the destruction of the beautiful 

 specimens. 



This very elegant creature inhabits the middle levels of the 

 littoral zone at Exmouth, in quiet sheltered pools amongst the 

 minor Algse, in company with the Cerithium reticulatum, which 

 outnumbers it by fifty to one. With it is also rarely found 

 the Murex adversus of authors, which we believe will turn 

 out, when the animal is seen, congeneric with the present spe- 

 cies. When our present animal is just captured it is veiy lively, 

 and creeps up a glass quickly. There can scarcely be a greater 

 contrast than between this animal and that of the Cerithium reti- 

 culatum, with which it has hitherto been confounded, and which 

 has the entire aspect of an elongated Rissoa, to which I think it 

 is even more closely allied than to Turritella and Aporrhais, 

 whereas our Murex tuhercularis is an undoubted Canalifer, though 

 it has evident relations with Euliina and Chemnitzia by the posi- 

 tion of the eyes and shape of the tentacula ; still the balance of 

 characters is greatly in favour of the present position. I believe 

 Mr. Alder and myself are the first and nearly contemporaneous 

 observers of this species. 



Murex et Buccimim, Linnaeus. 



Sectio YII. 



Testa gracilis, fusiformis, plicata, efi"usa, spiraliter striata, labio 

 externo y)lus minusve emarginato. Apertura subovalis. Colu- 

 mella planato-substriata. Operculum nullum. 



Murex gracilis, Montagu et auctorum, et nobis. 



Plenrotoma, Murex, Fusus, nonnull; Clavatula, Lamarck; Befrancia, 

 Millet ; Man ff ilia. Leach. 



Animal spiral ; ground colour white, aspersed throughout all 

 the organs with intense white flakes, mixed nearly equally with 

 pink lines, points and blotches ; these are minute, though varying 

 iu size and irregularly distributed. Mantle rather thick, not ex- 

 tending beyond the margm of the aperture, except the branchial 

 fold, which is often carried considerably beyond the canal of the 

 shell ; it also forms in the outer lip at the upper part a small, 

 open, slightly produced conduit that lines a deep scission in that 



