ART. 22 MIOCENE GASTROPODS AND SCAPHOPODS MANSFIELD 51 



Genus PETALOCONCHUS H. C. Lea 



PETALOCONCHUS ALCIMUS, new species 



Plate 9, figs. 2, 3, 4 



Petaloconchus sculpt uratiis [not H. C. Lea] Guppy, Agr. Soc. Trinidad Proc, 



vol. 10, p. 451, 1910. (In his list from Springvale.) 

 Petaloconchus sculpttiratus, var. domingensis Maury (not of Sowerby), Bull. 



Amer. Paleont., vol. 10, no. 42, p. 226, pi. 41, figs. 2, 4, 7, 1925. 



Shell solid, strong, thick walled, and large. Early part of shell 

 forms a loose and irregular spiral coil, which is angled with the 

 succeeding part. The following part up to about an inch in length is 

 more regularly spirally coiled, with gradually enlarging volutions. 

 The terminal part is usually coiled but the turns are very irregular 

 and loose. Whorl contour of the more regularly coiled part nearly 

 straight, slightly depressed medially and carinated at its lower 

 margin. The terminal tube is more rounded in outline. Sculpture 

 on the earliest coils of wide spaced, incremental transverse riblets, 

 and of two to three longitudinal lines being weakly nodulous at 

 the intersection with the ribs. The sculpture on the following more 

 regular coils not strong, consisting of incremental rugae and low 

 longitudinal lines. The two internal laminae are high, rounded at 

 the simimits, and arched toward each other. 



Petaloconchus sculpturatus H. C. Lea is a much smaller shell and 

 possesses stronger and more beaded, longitudinal sculpture lines, the 

 whorl contour on the more regular and closely coiled spire is more 

 rounded than in the new species. 



Type and locality (U. S. Nat. Mus. Cat. No. 352674) : Station 9195, 

 Springvale near Couva, Trinidad. 



Occurrence. — Upper Miocene: " Montserrat (Guppy), U.S. Nat. 

 Mus. Cat. No. 115456, and " Corona series " (Guppy) U. S. Nat. Mus. 

 Cat. No. 115457. 



Genus TURRITELLA Lamarck 



TURRITELLA GATUNENSIS CARONENSIS. new subspecies 



Plate 8, figs. 12, 13, 14 



TurriteUa gatuncnsis Maury, Bull. Amer. Paleont., vol. 10, no. 42, p. 229. pi. 42, 

 fig. 12, 1925. 



The specimens assigned to this new subspecies largely consist of 

 fragments, either of the early or later whorls of the shell. When the 

 form of the new subspecies is compared with TurriteUa gatuneiisis 

 Conrad it is found to be less attenuated, slightly more constricted 

 and less roundly excavated at the suture, and the two primary 

 spirals on the lower half of the whorl to be less distinct than on the 

 latter species. The early whorls on both are very similar. The 

 number of whorls is not known. The nucleus of the new subspecies 



