- oO - 



approach peltella o^ "being higher; such forns are distinguished from 

 even the unusuallj" strongly carinated and sulcated variants of the 

 peltella group "by the more decided emphasizing of the carina and 

 accompanying sulcus, the more conspicuous development of an ant- 

 erior sulcus, the presence of 3 more attenuated rostrum and the 

 absence of a lunule. On the other hand, the elongated variants of 

 peltella also apioroacli indifcna,- in this case the less sharply 

 rostrated and sulcated forms of indigena^ "but such mem"bers of the 

 peltella group may invsria'bly "be recognized "by their weaJcer carina, 

 "blunter rostrum and differentiated lunule. 



The young of indigene are proportionately higher than adults. 

 On either side of the anterior sulcation a few faint radiating 

 lines, su"bparallel to the sulcation, are occasionally present in 

 the interspaces "between the r-ugae. This species is a conspicuous 

 element among the Ledas of the fauna, "being surpassed numerically 

 only "be peltella . 



I. indigena is very closely related to I_. acvita (Conrad) (1) 

 which ranges from the Upper Oligocene Ghipola and Oak Grove "beds 

 of Florida to the Recent and also has a vv'ide R-eo-raphical ran^e. 

 The 3owden species is, hov/ever, in general terras smaller, less 



(1). Am. Mar. Conch., p. 52, pi. 6, fier. 1, 1832. :^or s.; nonymy 

 see Dall, Trans. V/agne r ?ree Inst. Sci., Philadelphia, 

 vol. 3, pt. 4, pp. 592-595, 1898. 



