2 4 ° PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
this stronger rib is not the first below the carina, but is preceded by a 
number of very fine striae, which are easily overlooked, and, indeed, in 
some parts of our specimen there seems to be a smooth space in their 
place. 
V. Ihering regards his specimen as a variety of P. discors. But, as has 
been demonstrated above, his P. discors is really the P. subcequalis of 
Sowerby, and, further, according to our specimens, there are other differ- 
ences between both, that make it advisable to separate P. unifascialis from 
P. subcequalis as a distinct species. The chief differences are: (i) The 
existence of only one spiral rib below the carina. (2) The position of the 
tuberculiform carina on the upper whorls, which, in the present species, is 
considerably below the middle, nearer to the lower suture, which gives to 
the whole shell a different appearance. (3) The number of tubercles on 
the carina, which is, in P. unifascialis , about 20 in the last whorl, against 
only 12 in P. subcequalis. 
Record of specimens : Mouth of Santa Cruz River, 1 sp. 
Distribution : Jegua quemada, Suprapatagonian beds (v. Ih.). 
Gen. GENOTA Ad. 
167. Genota cuevensis v. Ihering. 
PI. XXXVII, Fig. 2. 
1897 c ‘ v - Ihering, in: Rev. Mus. Paul., v. 2, p. 313, pi. 3, f. 10. 
Shell subfusiform, biconical. Whorls seven, in the upper part concave, 
with longitudinal ribs and spiral cords. Last whorl large, higher than the 
spire. Longitudinal ribs about 12-16, terminating in small nodes above, 
these nodes forming an angulation on the last whorl ; on the upper whorls 
the nodes are close to the lower suture. Spiral cords unequal on the 
lower part of the last whorl (below' the angulation), the larger ones are 
slightly nodulose, the nodes situated at the points of crossing with the 
longitudinal ribs. Mouth narrow, elongate, canal short, slightly recurved. 
Sinus of outer lip very slight, situated on the concave part of the whorl, 
near the suture. 
Measurements: Height, 16 mm; diameter, 8 mm (complete individ- 
ual). Height, 22 mm; diameter, 10 mm (apex gone). V. Ihering gives : 
Height, 32; diameter, 14 mm. 
