122 TRITONID^. 



necting link between the two groups, but certainly cannot be 

 safely removed from the vicinity of the latter, to which it is not 

 only allied by its operculum (which is entirely different from that 

 of Dolium), but so closely by the shell in some instances, that 

 the assignment of the generic position is quite arbitrary. 



The Tritons are distinctly tropical in distribution, no species 

 inhabiting the colder seas. The species are numerous and beau- 

 tiful, presenting a great range of variation in size and color ; 

 one species being almost the largest of gastropod mollusks, 

 attaining a length of one and one-half feet, whilst others, belonging 

 to the Epidromoid section, do not exceed one-half inch in length. 

 The cancellated forms are chiefly East Indian, and are dredged 

 in sand in deep water ; the West Coast of America species, 

 covered with a rough epidermis, are obtained in sandy mud at 

 from six to thirty fathoms depth. A number of species have a 

 world-wide distribution, which is doubtless due to their free- 

 swimming or pelagic larvae. These, unlike the Murices, but like 

 the Purpurse, are very different at first from the adult both in 

 animal and shell, undergoing a metamorphosis at a period subse- 

 quent to hatching. 



I adopt the well-known name Triton in preference to the pre- 

 viously given Tritonium of Cuvier, believing that the interests 

 of science are best conserved by keeping the nomenclature as 

 stable as possible. Triton has been used in other departments 

 of zoology, but so have many other generic names, which are 

 nevertheless accepted without question. 



Reeve says : " The Tritons are shells of much more solid 

 structure than the Murices or Ranellae, and of much more simple 

 growth. They are not furnished with any spines nor have they 

 any ramified branches like the Murices ; the rude manner in 

 which the whorls are convoluted seems rather to indicate that 

 their animal inhabitant, though possessing abundant power of 

 calcification, is of somewhat sluggish growth. The epidermis of 

 Triton is often remarkably thick, hairy and bristly, and is some- 

 times accompanied with small tufts of bristles. Another curious 

 peculiarity in these shells is the structure of the apex ; it appears 

 in numerous instances to be formed of horny substance, thinly 

 plated with shelly matter, and it is not an uncommon thing to 

 find exam.ples in which the calcareous plating is worn off so as 

 to expose the horny cast underneath. The columella of the 

 Tritons is generally covered with a bright coat of wrinkled 

 enamel, and the outer lip becomes thickened in a manner 

 exceedingly curious ; upon arriving at maturity the lip curls 

 under so as to form a deep, broad channel or gutter, and this is 

 then filled up to form the thickened lip. The varices are all 

 constructed in the same manner, each forming for a time the 

 margin of the aperture ; they are destined, it is conjectured, to 



