186 BALiENOPTEEID^. 



Proc. Zool. Soc. 1864, p. 208). The cranium is now in an extremely 

 imperfect condition, the maxillaries, premaxillaries, and nasals being 

 absent. There is, however, enough to show that it is not a Mega- 

 ptera, but belongs to the subfamily Balcenopterince, and probably, on 

 account of the great width of the external part of the orbital process 

 of the frontal bone, to the genus SibhahUus. The lower jaw is 52" 

 long, which would indicate an animal of about 18 feet, perhaps a 

 young individual of the species last described." — Flower, P. Z. S. 

 1864, 408, 



in. Dorsal fin high, erect, compressed, falcate, ahowt two-t?iirds of the 

 entire !e>i(/thfrom the nose, rectoral moderate, icith 4 short fitif/ers, 

 of 4 or Q Joints. Veiiebrce 50. Cervical vertebra sometimes auchy- 

 losed. Neural canal hroad, trif/omd, broader than high. Hibs 11 .11. 

 Balfeuopteiina, or Beaked Whales. 



8, BAL^NOPTERA. 



Balsenoptera, Sect. 1 (Balseiioptera), Grai/, Zool. Ereh. Sf Terr. 50. 

 BaL-enoptera, Gray, P. Z. S. 1847, 89 ; Cat. Ce.tac. B. 31. 1850, 31 ; 



P. Z. S. 1864, 226; Ann. Sf Mag. N. H. 1864, xiv. 352; Flower, 



P. Z. S. 1864, 393. 

 Balpenoptera (pars), Lacepede, Ceiac. 



Pterobalfena (pars), Eschricht, Nord. Wcdlthiere, 1849, fol. 

 Balfena (pars), Li)in. ; Mi'iUer, Zool. Dan. ; Illiger, Prodr. 242. 

 Rorqualus, sp., Dekay ; F. Cuvier, Cetac. 321. 

 Balfeua minimus, Knox, Cat. Whale, 14. 



Head elongate, flattened, throat and chest with deep longitudinal 

 folds and very dilatile. The dorsal fins compressed, falcate, two- 

 thii'ds the length of the body from the nose and behind the line 

 above the orifices of generation. The pectoral fins moderate, one- 

 eighth the length of the body, one-third the length of the body from 

 the head, with 4 short fingers of few joints. The humerus short, thick. 

 The radius nearly twice as long as the humerus. Lower jaw-bone 

 moderate, with a distinct high conical coronoid process. Vertebrte 50 ; 

 last very small. The first paii' of ribs undivided near the condyle. 



The lateral process of the second cervical vertebra elongate, pierced 

 at the base ; of the thii'd, fourth, and fifth cervical elongate, slender, 

 separate ; the lower with an angular bend below. The front ribs 

 simple, thick, with only a slight swelling on the inner edge near 

 the condyle. Tympanic bones obovate, short, ventricose. 



The lateral process of the second cervical vertebra expanded, broad, 

 with a large ovate perforation in the middle of its base, the U2)i:)er 

 and lower margins being broad and of nearly equal width, the upper 

 being, if anything, rather the broader of the two, very unlike the 

 lateral process of the same bone in PhysaJus. The neural arch high, 

 acute, with a rather high subcircular canal for the spinal marrow. 

 The bod}"- of the atlas vertebra oblong, transverse, with a subcylin- 

 diieal lateral process produced from the middle of the side. 



" Total number of vertebrte 48-50. Eibs 11 pairs. Orbital pro- 

 cess of frontal almost as broad at the outer end as the base. Nasal 

 bones rather narrow and elongate, truncated at their anterior ends, 



