MAMMALIA. 623 



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

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

 mae 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 LACEP^DE Hist. not. des Cetaces, Paris, xii. (1804) avec 

 fig. 4to. 



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

 Transact. Vol. 77, 1787 (also in the separate edit. Animal (Economy, by 

 B. OWEN, 1837, pp. 331 392). 



P. CAMPER Observations anatomiques sur la structure interieure et le 

 squelette de plu$ieurs especes de Cetaces, publ. par A. G. CAMPEB avec des 

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



F. CUVIER De THistoire natureUe des Cetaces. Paris, 1836, 8vo. 



W. KAPP Die Cetaceen zoologisch-anatomisch dargestelU. Mit Abbild. 

 Stuttgardt und Tuebingen. 1837, 8vo. 



D. F. ESCHRICHT Zoologisch-anatomisch-physiologische Untersuchungen 

 uber die nordischen Wallthiere, I. Bd. Leipzig, 1849, folio. Mit Tafeln 

 u. Holzschuitten. 



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*. 



1 Compare ESCHRICHT Untersuch. uber d. nord. Wattthiere, s. 71 75. 



2 W. SCORESBT Account of the Arctic Regions, Edinburgh, 1820, 8vo, i. p. 456; 

 compare V. BAER, OKEN'S Isis, 1826, s. 811, 1828, s. 927 932, KUESTER ibid. 1835, 

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



