52 2 Memoir Sears Foundation for Marine Research 



Relation to Man. In the western side of the Atlantic, chimaeroids are caught so 

 seldom that they are of no commercial importance. But their livers are rich in oil, which 

 has been used to a small extent in Scandinavia from earliest times as a remedy, internal 

 as well as external; it is also used somewhat on the Pacific Coast of Canada for cleaning 

 guns,^^ and it is said to be an excellent general lubricant. In New Zealand, where 

 chimaeroids are marketed for food, 360,000 pounds were landed in 1936— 1938, which 

 may serve as a representative year;^'^ and they are common market fish on the coast of 

 mid-China also.^^ 



Depth and Geographic Range. The depth range of the group as a whole extends 

 from close to the surface down to at about 1,400 fathoms, perhaps still deeper. Geo- 

 graphically, the range of one species or another is extensive also: eastern North Atlantic 

 from Morocco, the Azores and the Mediterranean to Iceland and northern Norway, 

 also inward to the Skagerrak; western North Atlantic from Cuba and the Gulf of Mexico 

 to the Nova Scotian Banks; western South Atlantic from southern Brazil to Tierra del 

 Fuego; Peru and Chile; eastern North Pacific from southern Alaska to southern Cali- 

 fornia; Hawaiian Islands region; Japan and China; southern Australia (New South 

 Wales, Victoria and Great Australian Bight); Tasmania; New Zealand; South Africa 

 from Natal in the east around to Walfish Bay in the west. 



Classification. The members of the order fall in three groups: A. with the front of 

 the head simply rounded or conical; B. with a long pointed beak; or C. with a curious 

 hoe-shaped proboscis (Fig. 127). Accordingly, three families are commonly recognized, 

 Chimaeridae, Rhinochimaeridae and Callorhinchidae (see Key, p. 522). 



Number of Genera and Species. Chimaeroids are one of the smaller major sub- 

 divisions of modern vertebrates; the number of known recognizable species totals only 

 24—28 at most, divisible into six genera. 



Geological History. The modern genera Chimaera and Callorhinchus have been in 

 existence since the Upper Cretaceous period. Other extinct representatives of the order 

 Chimaerae are known from as far back as the Lower Jurassic. And another assemblage 

 of fossil fishes, either classed as a separate order (Bradyodonti) of Holocephali,'* or 

 provisionally located there,^^ date back in geologic time to the Devonian. 



Key to Modern Families 



I a. Snout with flexible hoe-shaped terminal appendage (Fig. 127); caudal fin with a 

 distinct lower anterior lobe, its axis somewhat bent upward (tail heterocercal). 



Callorhinchidae, p. 558. 



I b. Snout rounded, conical or pointed, without hoe-shaped terminal appendage; caudal 

 fin without distinct lower anterior lobe, its axis not bent upward (tail diphycercal). 



31. Clemens and Willby, Bull. Fish. Res. Bd. Canada, 68, 1946: 72. 



32. Whitley, Fish. Aust., /, 1940: 237. 



33. In Chekiang; see Fang and Wang (Contr. biol. Lab. Sci. Soc. China, S, 1932: 283). 



34. Romer, Vert. Paleont., 1945: 578. 



35. Berg, Class. Fish., Trav. Inst. Zool. Acad. Sci. URSS., 5 (2), 1940; Engl. Transl., 1947: 383. 



