308 TRANSACTIONS OF THE WAGNER FREE 



These alone are rather numerous, and in spite of my desire to restrict de- 

 scriptions to well-characterized forms, I find that several require to be treated 

 as new. Each horizon seems to have a set of forms which are analogous to 

 those of preceding and subsequent horizons, and are, doubtless, genetically 

 connected with them. A few species not belonging to the genus have been de- 

 scribed by the older authors as Turritellas. Thus T. agtmh's Say and laqueata 

 and perlaqiieata of Conrad belong to the genus Turbonilla. T. vetusta Conrad 

 is probably a Proto. T. viotiilifera H. C. Lea, a doubtful species, T. carinata 

 of the same author (not of I. Lea), T. affinis Gay, and T. plana Nelson bear 

 specific names which are preoccupied in the genus. T. alternata Say is a 

 Bittium ; T. costulata Mighels and T. erosa Couthouy belong to Morch's 

 genus Tachyrhynchus . There are a number of species, such as T. alticostata 

 Conrad, constricta Emmons, eury?iome W\ut^t\6, Jluxio7ialis Rogers, multilira 

 Whitfield (not multilirata Ad. and Rve.), octonaria Conrad, prcBcincta Conrad, 

 secta Conrad, and siitiiralis Nelson (not of Sowerby), which have never been 

 figured. T. biseriata Conrad and T. terebriformis Conrad are catalogue names 

 of which no description or figure has been printed. 



In our recent seas there is a singular dearth both of species and individuals. 

 Very few are known even from tropical America, and only on the Pacific 

 coast do one or two species offer any great abundance of individuals. 



Turritella indenta Conrad. 



T. indenta Conr., Journ. Acad. Nat. Sci. Phila. viii. p. i8S, 1841 ; Proc. Acad. Nat. Sci. i. 

 p. 32, 1843 ; Am. Journ. Conch, iii. p. 258, pi. 21, fig. 13, 1S67. 



Older Miocene of the Chipola River, Florida, one mile below Bailey's 

 Ferry, Burns ; Chesapeake Miocene of Calvert Cliffs and Plum Point, Md., 

 Conrad and Harris. 



The figure given by Conrad is too cylindrical, and the sides of the 

 whorls insufficiently concave. The rib at the base of the whorls is often dou- 

 ble, and the surface of the whole shell when perfect shows fine, faint spiral 

 striae. 



Turritella indenta var. bipertita Conrad. 



T. bipertita {sic) Conrad, Proc. Acad. Nat. Sci. Phila. i. p. 326, 1842 ; Am. Journ. Conch, 

 iii. p. 258, pi. 2r, fig. I, 1867. 



Chesapeake Miocene of Petersburg, Va., Conrad. 



This differs from the type by the obsolescence of the two marginal cari- 

 nae of the whorls and the presence about the equator of several more or less 

 pronounced stride forming spiral threads by their interspaces. 



Turritella indenta var. martinensis Dall. 

 Shell differing from the type by the development of the marginal riblets 

 a little farther from the suture, and their frequent duplication by a fainter 

 thread; on the upper whorls the posterior thread is generally undulate or 



