69 CRETACEOUS GASTROPODA 
UIT. Family—OLIVID. 
The Oxrrip, represented by the well-known genera Oliva and Ancillaria, are, 
as regards structure and form of shells, most nearly allied to the Crrrarp, and 
form (through the sub-family aarprv# and the family Dozzp) a passage to the 
Cussipipm. The animals of the Ozrvipz are to some extent like young Crpr21D2, 
inasmuch as they have in front a kind of mantle-lobe, which also resembles that 
of the animals of the Zornarexztipz and Burts. In the Crrerxipx this 
mantle-lobe disappears totally, or very nearly so, while in the Ozzrzpzx it developes 
itself rather more strongly with advancing age. The dentition forms a marked 
difference in these two families. 
The existence of the anterior and posterior filamentose process and the enclosure 
of the latter in a separate groove at the suture admits of a convenient separation of 
the family into two sub-families, ozzviva and ancr~~ariInzZ. Gray includes in this 
family the genus Harpa as a sub-family also, warpazivz# or rather warprve, and, 
as the animals of Hapa do not seem to differ essentially, this classification appears 
acceptable. 
The fossil species of the Ozrrzpm do not date earlier than the cretaceous 
period. Of the ozzrzw three and of the avorzarzva. two species are known from 
these deposits. 
a. Sub-family—OLIVIN &. 
The first species of the ozrriv# was described by Professor Forbes from the 
South Indian ecretaceous rocks as Oliva vetusta (Trans. Geol. Soc., Lond., VIT., p. 134, 
Pl. 12, Fig. 23). Mr. H. Blanford (Mem. Geol. Surv., IV., p. 141,) mentions that 
an Oliva occurs in the Arrialoor beds at Ninnyoor; but we have not seen a trace of 
this shell, and cannot therefore pronounce an opinion on it. Forbes’ species appears 
to belong to Olivella, but it may be premature to make such changes, before well- 
preserved specimens have been examined. 
The second species is Oliva prisca, Binkhorst (Monog. Gastr. et Ceph. craie sup. 
de Limbourg, 1861, p. 71, Pl. V, A2, Fig. 14) from upper cretaceous beds; the 
species is based upon an imperfect cast, and appears rather doubtful; it could quite 
as well be a cast of a Cyprea or Erato. 
The third species, Olivella Mathewsonii, was lately noticed by W. Gabb from the 
cretaceous deposits of California (Pal. of Calif., I, 1864, p. 100, Pl. 18, Fig. 53). 
b. Sub-family—ANCILLARIN A. 
The two as yet known species belonging to this sub-family are dn. cretacea, 
Miiller (Petref. d. Aachner Kreide, 1851, p. 79, Pl. VI, Fig. 23) and An. elongata, 
Gabb. (Pal. Calif. I, 1864, p. 100, Pl. 18, Fig. 54). 
c. Sub-family—HARPINA. 
No cretaceous fossils, belonging to this sub-family, have as yet been reported. 
There are about five tertiary and fifteen recent species of Harpa known. 
