242 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
Record of specimens : Mouth of Santa Cruz River, 3 sp. 
Affinities: Within the genus Drillia we know a few species in which a 
collosity of the inner lip is combined with the character of slight develop- 
ment of spiral sculpture, but in most of them spiral lines are present at 
least in the lowermost part of the shell (on the canal). A complete lack 
of this sculpture is given for D. perpolita Dali (1890, p. 36, pi. 2, f. 2), 
Pliocene and Recent, West Indies and southern United States, but the 
latter has no callosity. Species, which have a callosity, but have traces 
of spiral ribs, are, for instance, D. kceneni Speyer (1867, p. 203, pi. 22, f. 
6, 7), Oligocene, Germany, D. sigmoidea Bronn, Pliocene, Europe. The 
most closely allied species seems to be D . limatula Conrad. In the 
Princeton Museum there are 7 specimens of this species from the Miocene 
of St. Mary’s River, Maryland, which agree in the complete lack of spiral 
sculpture and the presence of a callosity, as well as in the presence of a 
sutural depression with our Patagonian fossil. The differences, however, 
are: (1) the number of longitudinal ribs is less (9-1 1); (2) the sutural 
depression is less distinct, the ribs not ending so abruptly ; (3) the shape 
of the shell is less elongate. 
Gen. BORSONIA Bellardi. 
169. Borsonia patagonica Ortmann. 
PI. XXXVII, Fig. 4 a -°. 
1900 B. p. Ortmann, in Amer. Journ. Sci., v. 10, p. 377. 
Shell subfusiform, biconical ; whorls, about 6 ; last whorl a little larger 
than half of the shell, Whorls convex, depressed in the upper part, with 
a slight swelling just below the suture ; depressed part smooth (except 
for lines of growth), the rest ornamented by 10-12 longitudinal, rib-like 
swellings, which are slightly tuberculiform on the upper whorls ; on the 
last whorls they are rib-like, but less distinct, and tend to disappear 
toward the mouth. Besides the ribs, there are spiral cords on the lower 
part of the whorls, which are wanting on the depressed part, but continue 
on the last whorl upon the canal. Mouth elongate, canal of medium 
length. Outer lip with a moderately developed sinus, which is situated 
in the sutural depression. Columella with two plaits, of which the lower 
one is sometimes quite indistinct. 
