TRITONID. 121 
tionships with Magilus but rather with Vermetide. I do not 
know how closely it may be related to Nisea. 
NisEea, Marcel de Serres. 
Distr.—N. simplex, Serres (xliv, 39). 
Shell composed of a discoidal 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. 
Famity TRITONID2. 
Shell with varices, which are either few and irregularly dis- 
posed (Triton) or form a continuous row crossing the whorls 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°1°3), like the Doliide, ete. (The Muricidee 
have the teeth 1*1-1.) The dentition is illustrated on Plate xi, 
fig. 33. 
Conchological reasons mainly induce me to place the Tritonidz 
in close connection with the Muricide, rather than arrange them 
with the Cassidide and Doliidz, as indicated by their dentition. 
The Tritonide 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 Strombide, 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, ete. 7’. 
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 internally 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 tenioglossate mollusks, the 
affinities off the animal are on the whole closer, and those of the 
shell decidedly so, to Muricide. It may be considered a con- 
9 
