504 TUBE-BLADDERED GROUP. 



while there are also tusk-like teeth on the front of the tongue, and several 



longitudinal series of small ones on the hinder part of the same. In length the 



pectoral fins are medium. Growing to a length of 7 or 8 inches in the sea, the 



common smelt is also found in rivers and landlocked lakes, where its size is always 



considerably less. The allied candle-fish (Thaleichthys), of the Pacific coasts of 



North America, distinguished by its rudimental teeth, has flesh of such an oily 



nature that it can be burnt as a candle, although it is likewise used as food. 



For want of a collective English name, we must allude bv a 

 Coregonoids. . ... 



modification of their Latin title to an extensive group of mostly 



fresh- water salmonoids, among which the powan (Coregonus clupeoidcs), the 

 vendace (C. vandesius) of Lochmaben, and the pollan (G. 'pollan') of the Irish lakes, 

 are well-known British forms. In these fish the scales are not strikingly large ; 

 the cleft of the mouth is of moderate size, with a broad maxilla, either short or of 

 medium length, and not extending beyond the front margin of the socket of the 

 eye ; while the teeth, if present at all, are minute and deciduous, in the adult 

 usually remaining only on the tongue. The dorsal fin is not over long, and 

 the caudal is deeply forked. Whereas in the small size of their eggs these fish 

 resemble the smelts, they differ in having about one hundred and fifty blind 

 appendages of nearly uniform length attached to the intestine. As already 

 mentioned, these fish differ from the typical salmonoids in the relations of the 

 bones on the top of the skull, on which account they are regarded by Professor 

 Cope as indicating a separate family. Represented by over forty species, 

 ranging over Northern Temperate Europe, Asia, and North America, core- 

 gonoids are for the most part entirely fresh-water fishes, although a few make 

 periodical migrations to the sea, while the European schnsepel (C. oxyrhynchus) is 

 as much a marine as a fresh- water fish. Local in their distribution in Europe, 

 although as many as three different species may inhabit the same lake, coregonoids 

 are extremely abundant in all the fresh waters of North America (where they are 

 commonly known by the name of white-fish) ; and whereas all the British forms 

 are small, some of the continental species may attain a length of fully two feet. 

 The genus may be divided into groups, according to the conformation of the muzzle 

 and jaws. Of these, the first is represented solely by the schnsepel (C. oxyrhynchus), 

 which frequents the coasts and rivers of Belgium, Holland, Germany, and Sweden, 

 and occasionally wanders into British waters. It is easily distinguished by the 

 production of the extremity of the upper jaw into a conical fleshy snout projecting 

 beyond the lower, while its scales are more or less nearly circular. In length, this 

 fish grows to a foot and a half. As an example of the group in which the muzzle is 

 obliquely truncated, with the nose projecting, we may take the marane (C. 

 lavaretus), shown in the lower figure of our illustration ; this fish being widely 

 distributed in the lakes of the Continent, where its flesh is highly esteemed as food. 

 Whereas in the Austrian lakes this fish does not exceed 14 or 15 inches in length, 

 with a weight of half a pound, in Lake Constance it grows to a couple of feet in 

 length, and from 4 to 6 lbs. in weight. Living at great depths, this fish feeds 

 on worms, insects, and water-snails. While the powan belongs to another group 

 characterised by the vertical truncation of the muzzle, the pollan and vendace are 

 assigned to yet another division in which the lower jaw is longer than the upper, 



