MURICID^. 119 



tiire oblong, produced anteriorl}^ into a wide, subrecurved canal. 

 Operculum unknown. 



This, like the preceding genus, has only one properly authen- 

 ticated species ; and that is unquestionabl}^ very closely related 

 to Leptoconchus. The operculum is of the normal purpuroid 

 t3'pe, but like the shell, very thin, translucent and yellowish 

 white. 



Magilus, Montfort. 



Syn. — Campulotus, Gruett. (part). Tubulites, Davilla. Lep- 

 toconchus, Ruppell. 



Distr. — 5 sp. Coral Reefs, Mauritius, Red Sea. M. antiquus, 

 Lam. (xlv, 52, 53). 



Shell when j^oung, spiral, thin ; when adult, white, solid, 

 tubular, spiral for three or four whorls, the last prolonged into 

 an irregular straight or flexuous tube, solid posteriori}^, and with 

 a siphonal keel on the left side. Operculum ovate, nucleus sub- 

 lateral. 



In the " Genera of Recent Mollusca," the authors, following 

 Ruppell, distinguish the species of Leptoconchus from the single 

 species of Magilus. They thus describe the animal of the 

 former : 



The mantle-margin is greatly thickened and fleshy ; the tenta- 

 cles are small, broad and united at their bases ; the eyes are 

 small and black, on the outer side of the tentacles, near their 

 tips ; the foot is small, short, obtuse and rounded behind, with 

 a thin, expanded, disk-like lobe in front, and the siphon is obso- 

 lete. The genus differs from Campulotus (Magilus) not only in 

 the absence of the operculum, but in the shell never forming a 

 long tubular projection of the mouth as in that genus. It com- 

 prises but few species, which take up their abode in corals and 

 madrepores. 



Deshayes, in his " Conchology of the Island of Bourbon," 

 1862, describes a number of species of Leptoconchus as well as 

 the anatomy of one of them, confirms the non-existence of the 

 operculum and sustains the separation from Magilus. 



On the other hand, that experienced conch ologist, Mr. Gr. B. 

 Sowerby, in his introductorj^ remarks upon the genus Magilus, 

 in Conch. Iconica, xviii, 1872, unites Leptoconchus with that 

 genus. He saj^s : 



" The habits of this genus are very curious. The young fry, 

 after a short period of free locomotion, seems to find its way 

 into some hole in a growing madrepore, and then to become 

 stationary ; but as the substance grows around it, it would soon 

 become enclosed unless the growth of the shell kept pace with 

 that of the madrepore. In order, therefore, to keep its aperture 

 close to the surface, the two lips are extended in the same direc- 

 tion in the form of an irregular tube. The Magilus leaves its 



