INSTITUTE OF SCIENCE, PHILADELPHIA. 233 



Glyptostyla panamensis n. s. 

 Plate 13, figure 5. 



From the Miocene (?) of the isthmus, on the line of the Panama Canal, 

 at Vamos-vamos station, 19 kilometers from Colon. 



Shell pyriform, solid, thick, with about six whorls ; nucleus small, promi- 

 nent, marked with revolving striae ; shell covered with a closely reticulated 

 sculpture consisting of transverse and spiral ridges of about equal strength 

 and equidistant ; the transverse ridges in the earlier whorls are relatively 

 sparser and stronger, crenulating the suture, while on the later whorls the 

 spiral ridges override the others and are slightly more prominent ; the in- 

 terspaces are channelled and the spirals strap-like ; the transverse ridges are 

 less regular in shape; the spire is low, slightly compressed in front of the 

 distinct suture, with the latter marginated by the two adjacent spirals, which 

 tend to be larger than the others ; last whorl inflated, attenuated in front, 

 slightly expanded behind and laterally at the aperture ; canal produced, nar- 

 row, a little recurved; outer lip simple, smooth, marginated internally by a 

 broad callous deposit, narrower behind and at the canal, and not lirate; body 

 callous, smooth, with no subsutural lamina ; pillar callous, curved, with two 

 very strong, rather posterior rounded plaits, with the interspace between them 

 and probably the part of the pillar adjacent to the plaits spirally grooved. 

 Lon. of shell 30 ; of aperture and canal 26 ; max. lat. of shell 20 mm. 



It differs from G. crassitesta Gabb in its closer reticulation, more promi- 

 nent spire and more curved canal, if, indeed, the canal of Gabb's species is not 

 rather too straight in his figure. 



Genus MAZZALINA Conrad. 

 Mazzalina O'weni Dall. 

 Part I., p. 105, 1890. 

 Specimens obtained by Mr. G. D. Harris, of the U. S. Geological Sur- 

 vey, from various localities in Arkansas, lead to a doubt whether this form is 

 really distinct from Ftisus inaitratus Conrad. At all events, the specimens in 

 which the labial plaits are absent, and which in other respects do not seem to 

 differ from typical M. Oiveni, bear a striking resemblance to Conrad's shell. 



Genus MELONGENA Schumacher. 

 Melongena subcoronata Heilprin. 

 Part I., p. 120, i8go. 

 Since the above reference was printed, Mr. Willcox has been devoting 

 especial attention to collecting specimens of Melongena, and has now brought 

 together a magnificent series at the Wagner Institute. The result of an ex- 

 amination of this material is to raise a serious doubt as to the value of the 

 distinctions noted between this form and its undoubted descendant, M. coro- 

 nata. It seems highly probable that the two are not more than subspecifically 

 separated. 



