3418 Dr. J. E. Gray on the Whalebone-Whales. 
edge, on each side of the palate. The tympanic bones are large, 
conch-like, attached to the expanded periotic bones, which are 
articulated to the skull. The lachrymal and malar bones are 
small and thin, and are often lost in preparing the skulls. 
The Whalebone-Whales may be divided into two families, 
thus :— 
Fam. 1. Balenide. (The Right Whales.) 
The belly smooth, without any longitudinal folds. Dorsal fin 
none ; pectoral fin broad, truncated at the end. Maxillary bones 
narrow. Baleen elongate, slender, straight. 'Tympanic bones 
rhombic. Scapula higher than wide. 
A. Head very large; of adult, two-fifths the entire length. Baleen elongate, 
slender, with a single series of very fine elongate central fibres, forming 
‘a fine flaccid fringe. Enamel thick, polished. 
1. BaLana. 
Ribs 13; the first like the others, single-headed ; the tympanic 
bone rhombic, aperture oblong, only shghtly contracted at the 
upper end, and about two-thirds the length of the bone. (Proc. 
Zool. Soc. 1864, p. 201, f. 1.) 
1. Balena mysticetus, Cuvier, Oss. Foss. v. t. 25. f. 9, 10 (adult). 
(Greenland Right Whale.) 
Balena mysticetus arctica, Schlegel, Abh. 36. 
Nordhval, Eschr. 
Hab. Northern Sea, Greenland. 
2. Balena Biscayensis, Eschr. & Van Ben. 
Hab. The Bay of Biscay. I have seen no remains of this 
Whale. 
3. Balena marginata, Gray, Zool. Ereb. & Ter. 48, 61. f. 1. 
Only known from some plates of baleen received from 
Western Australia. This is undoubtedly a very distinct species. 
The baleen is of nearly the same structure as that of the Green- 
land Whale; but we do not know what may be the form of the 
first ribs or of the bones of the other parts of the skeleton. 
B. Head large; of adult, about one-fourth the entire length. Baleen elongate, 
broad at the base, with several series of rigid central fibres, forming a 
rigid fringe. Enamel thin. 
2. Eusarzna, Gray, Proc. Zool. Soc. 1864. 
Ribs 15; the first like the others, single-headed. Tympanic 
