1865.) DR. J. E. GRAY ON NEW SPECIES OF DOLPHINS. 735 
Tacchus leucomerus, Gray. 
Albino var. Simia argentata, Linn. 
Hab. Bolivia. 
To the species of Midas described by M. Isidore Geoffroy may be 
added, from the British Museum Collection. 
1. MIDAS LEUCOGENYS. 
Black ; back and outside of hinder limbs washed with reddish grey ; 
face and lips black, with a large triangular white spot under each 
cheek. 
Hab. Brazil. 
2. MipAsS RUFOVENTER. 
Midas elegantulus, Slack, Proc. Acad. N.S. Philad. 1861, p. 463. 
Jacchus rufoventer, Gray, Ann. N. H. xii. p. 398 (1843), 
Hab. Brazil. 
This species is at once distinguished from M. labiatus, with which 
it has been confounded in the collection, by the spot on the crown of 
the head and the nape, and by the rufous colour of the under part 
coming much more forward, nearly to the throat. In M. ladbiatus 
the black terminates on the front of the chest, ina straight line. It 
differs from M. mystax in the small size of the whiskers, andin the 
body not being black, but red below. 
3. DESCRIPTION OF THREE SPECIES OF DOLPHINS IN THE 
Free Museum At Liverroou. By Dr. J. E. Gray, F.R.S., 
F.L.S., V.P.Z.S., etc. 
Mr. Thomas Moore, the Curator of the Free Museum at Liver- 
pool, has kindly submitted to my examination the skeletons of three 
Dolphins, which have lately been most liberally presented to that 
institution by Captain Walker, of the ship ‘Trenton.’ During a 
voyage from India to Liverpool the Captain not only collected the 
specimens, preserved the bones, the tails, and the pectoral fins, but 
he also made drawings of the animals when they were first caught. 
These drawings Mr. Moore has sent to me with the skeletons for 
examination and comparison. A reduced representation of each of 
these accompanies this paper. The drawings are accompanied by 
models cut in pasteboard of the dorsal fins, evidently made by tracing 
the fins on the paper. In two of these the end of the fin is much 
produced backward, leaving a concave hinder margin. In the other 
the end is not so much produced, as the hinder edge is nearly 
straight. 
The skull of each of the animals has the bladebones attached to it. 
The skulls indicate two very distinct species of Dolphins, belonging 
to different sections of the genus; and the drawings show that two 
animals having nearly similar skulls are very differently coloured—a 
fact which it is very interesting to have so verified. 
