2T6 University of Texas Bulletin 



VASCOCERAS aff. GAMAI Choffat 

 PI. 15, figs. 3-5 



1886: Vascoceras Gamai Choffat, Especes nouv. ou peu conn., p. 54, pi. 7, figs. 1-4; 

 pi. 8, fig. 1; pi. 10, fig. 2; pi. 21, figs. 1-5. 



In the collection made by Dr. Angermann I found a cepholopod which 

 probably represents a juvenile stage of some species belonging to the group 

 of Vascoceras Gamai. Judging from the petrographical aspect of the 

 specimen I suppose that it was found in the upper horizon of the Salmurian 

 of Cerro del Macho. Its features are : 



Shell relatively small, quite involute with whorls of a subquadrangular 

 rounded cross-section, broader than high. The umbilicus is narrow and 

 probably deep, the umbilical wall is abrupt. The flanks are flattened, the 

 ventral part rounded. On the umbilical border we count seven thick, 

 round, and pointed nodules. From each of these starts either a pair of 

 ribs or a simple rib, which curves slightly forward and crosses without 

 interruption the ventral portion. Between these main ribs one or two 

 secondary ones are intercalated. These begin above the umbilical border, 

 but on the venter are as strong as the main ones. The ribs are thick, 

 broad, rounded, wider than the interstices by which they are separated. 

 On the ventral shoulders the ribs seem to have u tendency toward a slight 

 thickening but real nodules do not form there. On the anterior part of 

 the last whorl, and especially on the ventral region, the ribs seem to dis- 

 appear. This region is partially corroded but in a place which is well 

 preserved one notes clearly that the ribs are very low and scarcely per- 

 ceptible on the line of symmetry. 



Figure 3. Suture, Vascoceras aff. gamai Choffat 



The suture is very little ramified. The external lobe has two branches 

 and is quite deep and narrow; the external saddle is little ramified, broad 

 and rounded ; the first lateral lobe is less deep than the external one and 

 rather narrow. The first lateral saddle is little ramified and resembles in 

 its form the external one, but is narrower. 



Our specimen resembles the juvenile form figured by Choffat in figure 4 



