DELPHINIDAE 267 
small, narrow, and ovate. Typified by C. heavisilvi, from the 
southern seas. C. eutropia is a very distinct form from the same 
seas, known only by the skull, and referred provisionally to this 
genus. 
Orcella..—Teeth 12 to 44, small, conical, pointed, rather closely 
set, and occupying nearly the whole length of the rostrum. Skull 
subglobular, high. Rostrum nearly equal in length to the cranial 
portion of the skull, tapering. Pterygoids widely separated from 
one another. Manus of moderate size, not elongated, but some- 
what pointed. All the bones of the digits broader than long, 
except the proximal phalanges of the index and third fingers. 
Dorsal fin rather small, placed behind the middle of the body. 
Two species, both of small size—0O. brevirostris, from the Bay of 
Bengal, and O. fluminalts, from the Irawadi river, from 300 to 
900 miles from the sea. Our present knowledge of the anatomy, 
geographical distribution, and habits of these interesting Cetaceans 
is almost entirely due to the researches of Dr. J. Anderson.” 
Orca2—Teeth about 12, occupying nearly the whole length of 
the rostrum, very large and stout, with conical recurved crowns, 
and large roots, expanded laterally and flattened, or rather hollowed, 
on the anterior and posterior surfaces. Rostrum about equal in 
length to the cranial part of the skull, broad and flattened above, 
rounded in front; premaxille broad and rather concave in front of 
the nares, contracted at the middle of the rostrum, and expanding 
again towards the apex. Pterygoids of normal form, but not quite 
meeting in the middle line. Vertebre: C 7, D 11-12, L 10, 
C 23; total 51 or 52. Bodies of the first and second and some- 
times the third cervical vertebre united; the rest free. Pectoral 
fin very large, ovate, nearly as broad as long. All the phalanges 
and metacarpals broader than long. General form of body robust. 
Dorsal fin near the middle of the back, very high and pointed. 
Anterior part of the head broad and depressed. 
The animals composing this genus are met with in almost all 
seas from Greenland to Tasmania, but the number of species is still 
uncertain, and possibly they may be all reduced to one. They are 
readily known, when swimming in the water, by the high, erect, 
faleate dorsal fin, whence their common German name of Schwert- 
fisch (Sword-fish). By English sailors they are generally known as 
“Grampuses” or “Killers.” They are distinguished from all their 
allies by their great strength and ferocity, being the only Cetaceans 
which habitually prey on warm-blooded animals, for, though fish 
form part of their food, they also attack and devour Seals, and 
1 Gray, Cat. Seals and Whales in Brit. Mus. p. 285 (1866). 
2 Anatomical and Zoological Researches, comprising an Account of the Zoological 
Results of the two Expeditions to Western Yunnan, tn 1868 and 1875 (1878). 
3 Gray, Zoology of Erebus and Terror, p. 33 (1846). 
