^^iioi!''] proceedinCtS of the national museum. 175 



Eupleura, vjir. limata Dall. 



Eupleura murici/ormis Brod., var. limata Dall, op. cit., p. 140, 1890. 



At tbe bead of the Gtilf of Calit'oniia, near the estuary of the Colo- 

 rado River, is found, botli recent aud in tbe Postpliocene of tbe vicin- 

 ity, a variety wbicb I bave called limata, in wbicb tbe intervarical nodes 

 are obsolete ; tbe whole surface nearly smooth ; there are but two or 

 three varices in all, aud they are narrow and not prominent. This va- 

 riety reaches a length of 40 and a width of 18.5 millimetres. 



Tbe depauperatecharacter of tills variety is very probably due to tbe 

 freshening of the water by the outtlow from the river and the barren 

 sandy shore upon wbicb it lives. 1 bave shown elsewhere in connec- 

 tion with Melongena that the rocky oyster reefs furnish tbe rough and 

 tlie sandy shores the smoother specimens and this generalization prob- 

 ably affects most caualiferous Gastropods. 



Eupleura caudata Say, 



(Plate VI, Fig. 2.) 



lianeUa caudata Say, Joiirn. Acad. Nat. Sci. Phil., ii, p, '23G, 1822. 



Eupleura muric'tformis Tryou, Man., ii, p. 158, ex parte, non Broderip. 



Eupleura caudata Stimpsou, Am. Joiini. Conch., i, p. ^iS, Pi. 8, Fig. 5, 18G5; Dall, 



Hull. :57, U. S. Nat. Mas., p. 120, Pl. 50, Fig. 11, 188U ; Traus. Wagner Imfc.,lii, 



p. 141, 1800. 

 Euphura " clathrata Gray" Calkius, Proc. Davenport Acad. Sci., 1878, p. 234. 



llAiuTAT: Atlantic coast of tbe United States from Cape Cod to the 

 Florida Keys, U. S. Fish Commission. Fossil in tbe Pliocene of South 

 Carolina and Florida and the Postpliocene of most of the Atlantic 

 coast. 



The shell sometimes reaches a length of 27 to 30 millimetres. 



Tlie specimen figured measures 23.3 long, 12.5 wide, and 8.5 millimetres 

 in lesser sectional diameter, taken from one side of tbe last whorl to 

 tbe ()i)posite side at right angles to the plane of tbe aperture aud verti- 

 cal to tbe intervarical dorsal node. 



This species has been much confused, and the group to which it be- 

 longs, though containing but few species, i)resents as pretty a series of 

 moditications in space and time as any evolutionist could wish to see. 

 Exclusive of E. pectinatQ, of which I have only seen figures, and Hanella 

 pulchra (.TViiy, wbicb belongs elsewhere, I recognize among the recent 

 ibrms one well-established s[)ecies on the Atlantic coast, with a sub- 

 species or geographical race on the Gulf coast and some of the northern 

 Antilles. On the F*acific coast we have two si)ecies, one of which is 

 constant and well marked (the E. nitida Broderip), tbe other very vari- 

 able and possessing a number of varieties wbicb may be geographical or 

 simply mutations, we are not yet in a position to decide wbicb. J^. 

 murici/ormis Broderip, which is the oldest name lor the latter, has been 

 referred to an untigured " Ranella clatiirata " of Gray, from the Atlautic, 

 which is not only a more modern name than Broderip's, but tbe char- 

 acters given for it are not compatible with the Pacific shell. 



