Dr. H. Burmeister on some Cetaceans. 101 
On Delphinus microps. 
Of this species we have now three skulls in the museum, it 
being the commonest species on the coast of Brazil south of the 
equator. I saw many troops of them during my voyage in the 
sailing vessel which first brought me here. 
The animal is of the size and colour of your Delphinus Walkeri 
(fig. 100), and I think it may be the same species, if the skull is 
not very different. My three skulls are of equal size, 17 Rhenish 
(=18-15 English) inches in length, and 7 (=74 English) inches 
in breadth at the widest point on the temporal arch, beneath the 
fossa temporalis. They have from forty-seven to forty-nine teeth 
in the upper jaw, and from forty-four to forty-eight in the lower; 
but the number seems to be variable, as the first and last teeth 
are very small, and often wanting on one side when present on 
the other. The upper jaw always has some more teeth behind, 
and the lower jaw probably some more in front. The form is 
exactly like your figure (pl. 25), even the deep groove on the 
right side of the frontal tubercle being the same, and the occi- 
pital crest very prominent in front, perhaps more so than in 
your figure. The teeth are six to an inch in the middle of the 
aw. 
In its general form the skull is nearly allied to that of Steno 
attenuatus, which I received last year from a friend on his return 
_from Europe in a sailing vessel. This vessel took the animal in 
the middle of the Atlantic, south of the line; and my friend 
preserved the skull for me, the animal having been eaten by the 
sailors. The skull is exactly 17 inches long, and agrees pre- 
cisely with your figure in the ‘ Voyage of the Erebus and Terror,’ 
1, 28. 
: Lastly, I have also received the skull of Delphinus Styx (Voy. 
Ereb. and Terr. pl. 21) from a sailor, who captured the animal 
near Madeira. I am also in expectation of an entire well-pre- 
served skeleton of a Dolphin taken in the river two miles above 
Buenos Ayres ; but the owner would not give me the bones till 
to-day. 
Orca magellanica, n. sp. Pl. IX. fig, 5. 
This animal is known only by a skull found on the shore of 
the province of Buenos Ayres, in lat. 38° 50'S., near the mouth 
of the small Rio del Cristiano muerto. It seems to be very like 
Orca capensis, but rather more slender, as is proved by the fol- 
lowing measurements of the skull, compared with the same in 
Orca gladiator and capensis, as given by Dr. Gray in his ‘ Cata- 
logue of Seals and Whales, ed. 2. pp. 280 & 284. 
