MAMMALIA. 623 



Family VIII. Cetacea (in stricter sense) s. Cetacea carnwora. 

 Spiracles (external apertiires of nostrils) on the top of head. Mam- 

 maj inguinal. Teeth different in different genera, conical, never 

 molars with flat crowns, in some the teeth in an embryonic state 

 only. Body destitute of hair. 



Compare Lacepede Hist. not. des Cetaces, Paris, Xli. (1804) avec 

 fig. 4to. 



J. Hunter Observations on the Structure and (Economy of Whales, Philos. 

 Ti'ansact. Vol. 77, 1787 (also in the separate edit. Animal (Eco7iomy, by 

 R. Owen, 1837, pp. 331—392)- 



P. Camper Observations' anatomiques sur la structure inferieure et le 

 sqioelette de plusieurs especes de Cetaces, publ. par A. G. Camper avec des 

 notes de G. Cuvier et un Atlas de 53 pi. Paris, 1820, 4to. 



F. Cuvier De VHistoire naturelle des Cetaces. Paris, 1836, 8vo. 



W. Rapp Die Cetaceen zoologisch-anatomisch dargestellt. Mit Abbild. 

 Stuttgardt und Tuebingen, 1837, Svo. 



D. F. EscHRiCHT Zoologiscli-anatomisch-physioloyische Untersuchungen 

 iiber die nwdischen Wallthiere, i. Bd. Leipzig, 1849, folio. Mit Tafeln 

 u. Holzschnitten. 



The true cetaceans live almost all in the sea exclusively. Amongst 

 them the largest animal species are met with. A thick layer of 

 fat under the cuticle protects these animals from the cold, and 

 diminishes their specific gravity. This layer of fat passes without 

 any definite distinction into a firmer and more fibrous layer be- 

 neath the cuticle, so that the blubber forms a whole with the 

 corium. The skin is without hair; but in the foetal state in 

 Dolphins, and even also in the whales in the adult state, some 

 bristles are set upon the upper and sometimes also upon the lower 

 jaw \ That water can be ejected from the blow-holes like a fountain, 

 experienced observers are disposed to doubt; the animals breathe 

 (blow) through the apertures, and the vapour mingled with the air 

 may be seen as a condensed column, especially in cold regions, 

 since the animal heat of these creatures is greater than in most 

 mammals ^ 



^ Compare Eschricht Untersuch. iiber d. nord. Wallthiere, s. 71 — 75. 



® W. ScoRESBT Account of the Arctic Regions, Edinburgh, 1820, 8vo, i. p. 456 • 

 compare V. Baer, Oken's Isis, 1826, s. 8it, 1828, s. 927 — 932, Kuester ibid. 1835, 

 s. 85, HOLBOELL in Eschricht's Untersuchungen, 193, 194, &c. 



