312 TRANSACTIONS OF THE WAGNER FREE 



Tlie species is related to perattenuata Heilprin, ainiberlandia Conr., 

 variabilis and exaltata Conr., the two last of which are probably identical 

 species. 



T. altilira Conrad, from the Gatun Miocene, is so badly figured as to be 

 a doubtful species ; it is obviously closely allied to the present form. The 

 form figured by Gabb from Sapote, Costa Rica, Miocene (Journ. Acad. Nat. 

 Sci., 2d Ser. viii. p. 341, pi. 44, fig. 9, 1874) under the name of " rt/Z/Z/ra/rt 

 Con.," whether identical with Conrad's altilira or not, is evidently allied to 

 our species, but more drawn out and with stronger beading on the ridges. 

 T. terebrifonnis is sometimes finely undulated on the ridges by the lines of 

 growth, but this is less common in the Northern shells than in those from 

 Chipola — a difference recognizable as due to latitude. T. tornata Guppy, from 

 the old Miocene of Santo Domingo, is another form of the same group very 

 similar to T. altilira. 



Turritella chipolana n. s. 

 Plate 22, figure 24. 



Older Miocene of the Chipola beds, Florida, Burns. 



Shell strong, acute-conic, of eighteen or more whorls ; nucleus decollate ; 

 early whorls showing one undulated posterior and one plain anterior spiral 

 rib, with a less prominent one behind the suture ; a fourth appears between 

 the first two, and on the later whorls nearly equals them in size ; on the last 

 whorl we find at the basal margin a squarish primary spiral under which the 

 suture is closely and evenly appressed; behind this is the most prominent spiral, 

 then two slightly smaller, between which is the equatorial sulcus, in the mid- 

 dle of which is a very fine, sharp undulated line; between the last-mentioned 

 primary and the suture behind it are two somewhat obscure spirals succes- 

 sively smaller; the equatorial and two anterior interspaces are nearly equal 

 in width and channelled rather than excavated; the whole surface of the shell 

 is covered with obscure spiral striations ; the transverse sculpture undulates 

 all the spirals on the later whorls and is formed by the lines of growth, which 

 in some specimens are elevated and imbricate at intervals ; the whorls are 

 strongly sculptured to the tip, and rather rounded, the suture distinct, but 

 nowhere discontinuous ; the base in the young is flattish, somewhat excavated 

 inside the marginal rib, the inner edge of the excavation forming a sort of 

 disk about the pillar ; in the adult the base is more convex, but without dis- 

 tinct spiral ribbing ; the pillar is thin, arched, and so twisted that the axis of 

 the shell, vertically regarded, is somewhat pervious ; the aperture is somewhat 

 rounded. Lon. of shell 68; max. diam of base 18 mm. 



This species, which appears to be rare, is one of the most elegantly 

 sculptured of the group. It recalls T. mississippiensis Conrad, from the 

 Vicksburg, which is flatter and less ornamented. T. indenta var. mixta has a 

 similar succession of spirals on the whorl, but they are comparatively feeble 



