TRITONID^. 121 



tionships with Magilus but rather with Yermetidse. I do not 

 know liow closely it may be related to Nisea. 



NiSEA, Marcel de Serres. 



Distr. — N. simplex^ Serres (xliv, 39). 



Shell composed of a diseoidal portion and of two tubes ; the 

 last whorl recurved upon itself in the same way as Anostoma, 

 in two tubes of variable length and less sinuous than the single 

 tube of Magilus. (Fossil.) Relationships very doubtful. 



Family TRITONID^. 



Shell with varices, which are either few and irregularly dis- 

 posed (Triton) or form a continuous row crossing the wTiorls on 

 opposite sides (Ranella). The number of varices does not exceed 

 two to each whorl, whilst in Murex the smallest number is three. 

 Operculum annular, with subapical or central nucleus. Mantle 

 enclosed, siphon straight, foot small. Lingual membrane with 

 teeth in seven rows (3'l*3),like the Doliidte, etc. (The Muricidse 

 have the teeth 1*1"1.) The dentition is illusti'ated on Plate xi, 

 fig. 33. 



Conchological reasons mainly induce me to place the Tritonidse 

 in close connection with the Muricidse, rather than arrange them 

 with the Cassididse and Doliidoe, as indicated by their dentition. 



The Tritonidse first positively appeared in the eocene strata ; 

 the genus Spinigera, d'Orb., from the cretaceous, being now 

 referred, more correctly I think, to the family Strombidse, and 

 Trachytriton, Meek, also cretaceous, does not belong certainly 

 to the family. 



Triton, Montf. 



Etym. — Triton^ a sea-deity. 



Syn. — Tritonium, Link. Charonia, Gistel. Aquilus, Montf. 

 Cabestana, Bolt. Lampusia, Schum. Ranularia, Schum. Colu- 

 braria, Schum. Linatella, Gray. Lotorium, Montf. 



Distr. — 105 sp. Tropical seas, world-wide ; low water to fifty 

 fathoms. Fossil, 80 sp. Eocene — ; Europe, Chili, etc. T. 

 variegatus, Lam. (xlvi, 54). 



Shell oblong ; spire prominent, whorls with a few remote 

 and non-continuous varices ; columella rough or smooth ; canal 

 recurved, short or long ; outer lip internallj^ crenated or denti- 

 culated. 



Operculum ovate, its growth annular either from a subapical 

 or submarginal nucleus. 



Whilst the lingual armature of Triton allies it closely with 

 Dolium, etc., among the so-called tsenioglossate mollusks, the 

 affinities of the animal are on the whole closer, and those of the 

 shell decidedly so, to Muricidae. It may be considered a con- 



