176 NEW WEST AMERICAN SHELLS DALL. 



Although Say's name was published in 1822, it has been referred to 

 this alleged E. clathrata Gray (1830) as a synonym! 



The Atlantic form, the typi(5al caudata, is found on the Atlantic coast 

 from Cape Cod to the Florida Keys, and it is recognizable when adult 

 by its smaller size, more cancellated sculpture, and by having Ave 

 transverse riblets on the back of the last whorl between the two varices, 

 and three in front. This is the form figured by Say, and which must 

 retain the specific name. It is also fossil in the Postpliocene, if not 

 also in the Pliocene, of the greater part of the Atlantic coast. 



Eupleura caudata, var. sulcidentata Dall. 

 (riate V, Fig. 4.) 

 Eiqylciira caudata, \HT. sulcideittata Dall, Trans. Wagu. Iii.st.,iii, p. 147, 18'J0. 



Gulf coasts of the United States and the Florida Keys ; Charlotte 

 Harbor, in shallow water among alg;e, Dall. Coast of Cuba, Gundlach. 



The form figured in the Pliocene fossils of South Carolina by Tuomey 

 and Holmes is the typical caudata, as is that of the South Carolinian 

 Postpliocene. Calkius's specimens were young and looked much like | 

 the young of the Pacific coast species. The Pliocene fossils tend to- 

 ward an intermediate character, as might be expected, I have seen 

 no genuine caudata from the Miocene, though the shell figured by Eni- 

 nious looks as if it was this s|)ecies. 



This variety is characterized by its thinner, more expanded, and re- 

 curved varices; its generally whiter color, larger size; and has in the 

 adult, on the back, three intervarical, tlattish, transverse ribs and two 

 or three in front. The spire is rather more elevated than in the typical 

 caudata, and, except on the varices, the spiral threads are often absent 

 or obsolete. Young shells have more intervarical ribs than adidts. In 

 the American Marine Conchology Mr.Tryon, by some oversight, refers to 

 the synonymy of IJ. caudata a Fusus iryruloides of De Kay, which a[)- 

 l)ears to have been founded on an immature Mclongcna. It is possible 

 he meant to write Fusus imhricatus J)e Kay, which is described on the 

 same page as the other, and figured on the same plate. This figure some- 

 what resembles a young Eupleura, but from the description one would 

 be disposed rather to refer it to an immature Urosalpiux. 



This is the southern race of E. caudata, readily distinguished from 

 the latter by its usually pure white and less earthy shell, its more slop- 

 ing si>ire, less angulated varices, and the sulci between the teeth of the 

 aperture. It has a smoother, less reticulated shell, with the spiral 

 sculpture obsolete, usually few intervarical sharp transverse ridges, and 

 the spines at the shoulder absent or less pronounced. The throat is 

 often i)urple or brown, against which the white teeth of the outer lip 

 sliow prettily. It has not been found north of Florida on the Atlantic 

 coast. It frequently reaches a larger size (25 millimetres) than the 

 specimen figured, which measures 11) millimetres long, 10 millimetres 

 wide, and a lesser diameter ou the section of the last whorl of G milli: 

 metres* 



i 



