358 PROCEEDINGS OF THE ACADEMY OF [April, 



Turritella gatunensis Conrad. PI. XXVII, figs. 4, 5, 9. 



Turritella gatunensis Conr., Pacific R. R. Rep., VI, p. 72, PI. 5, fig. 20. 



Dall, Trans. Wagner Inst., III. p. 310, PI. 17, fig. 10. 

 Turritella conradi Toula, Jahrb., p. 694, PI. 25, fig. 4. 

 Not Turritella gatunensis Conrad, Gabb, Journ. A. N. S. Phila., VIII, p. 342, 



PI. 44, figs. 10, lOo ( = T. tristis. 6 ) 



This fine species stands close to T. planigyrata Guppy, but differs 

 from it by having the upper part of each whorl much more excavated 

 or contracted. Dall's figure, cited above, is not very characteristic 

 of the typical gatunensis, and Gabb's figures of the form from the 

 black shale of Oronli Creek, Talamanca, Costa Rica, represent a differ- 

 ent species. 6 The Pliocene T. subannulata Dall seems to be related 

 to T. gatunensis. 



Turritella uvasana Conr., from the Calif ornian Eocene, is not very 

 closely related to T. gatunensis, the spiral threads being subequal, 

 and the upper part of the whorls not nearly so much excavated as in 

 the Panamic species. T. uvasana is much nearer T. tristis in sculpture, 

 but on comparing specimens it is seen that uvasana has many more 

 spirals, longer and less convex whorls. 



T. gatunensis has been reported from Vicksburg Eocene of Florida 

 and from the Oligocene of Ballast Point (Dall, I.e.). It belongs to a 

 type widely spread in Tertiary and recent faunas. 



Turritella altilira Conrad. PI. XXVII, figs. 2, 3. 



Turritella altilira Conr., Pacific R. R. Reports, VI, p. 72, PL 5, fig. 19 (Gatun). 

 Not Turritella altilirata Conrad, Gabb, Journ. A. N. S. Phila., VIII, p. 341 



PI. 44, figs. 9, 9a (Sapote, Costa Rica). 

 Turritella gabbi Toula, Jahrb., p. 695, PI. 25, fig. 5 (Gatun). 



This magnificent Turritella was rather rudely figured by Conrad. 

 It is a common and characteristic species of the Gatun beds. It 

 tapers slowly and, judging from the broken specimens seen, must 

 attain a length of upwards of 100 mm., with a basal diameter of 18 

 mm., and probably over 25 whorls. 



Each whorl bears two very high spiral ribs, crenulated at their 

 summits, the lower rib narrow, the upper wider, usually but not always 

 double at the ridge, or with a lower cord below the main one. The 

 deep concavity between the ridges has sculpture of several unequal 

 spiral cords, more or less crenulated; and the whole surface, when 



e Turritella tristis n. sp. A long, slowly tapering shell with strongly convex 

 whorls, the intermediate and lower ones with sculpture of five sharp, strong spiral 

 cords, much narrower than their concave, spirally striate intervals. The largest 

 fragment has 9 whorls in a length of 30 mm., the last whorl about 9 mm. in 

 diameter. Gabb has figured this in his PI. 44, fig. 10. Others are larger, diameter 

 about 15 mm. The interstitial strue are not very well-preserved, but are visible 

 in places. Black shale bed, Oronli Creek, Talamanca. 



