216 SUB-CLASS (AND ORDER) TELEOSTEI. 



lean ; male parrs may become sexually mature and fertilise the eggs of a 

 full-grown female ; will hybridise (artificially) with the trout and charr ; 

 not a highly variable species and change of conditions is fatal. The 

 various kinds of British trout are probably all varieties of the same species, 

 as they will freely cross, but three species may for convenience be dis- 

 tinguished : S. trutta Flem., sea- or salmon-trout, phinok, sewin, a migra- 

 tory species ; S. jario L., the brook trout ; and S, levenensis Walker, 

 Loch Leven trout. To these the bull-trout, S. eriox, and great lake- 

 trout, S. ferox, may possibly be added. 



S. alpinus L., the charr, breed Nov. to Dec. ; redd usually in 

 gravelly shallows in the lakes (the Windermere charr is known as S. 

 willughbii) ; the charrs are migratory or non-migratory and inhabit 

 the deep waters of lakes ; there appears to be one British species 

 with several varieties. S. fontinalis Mitchell, f. w. of Brit. N. 

 Amer., acclimatised in Britain. Oncorhynchus Suckley, anadromous fish 

 in American and Asiatic rivers flowing into the Pacific ; O. tschawytscha, 

 the Calif ornian salmon ; Brachymystax Gthr., Siberian rivers ; Lucio- 

 trutta Gthr. (Stenodus Rich.), Arctic N. Amer. ; Plecoglossus Schley., 

 f. w. of Jap. and Formosa. Osmerus L., smelts, migratory, 

 ascending rivers to spawn and frequently becoming resident in them, 

 Atl. coasts of N. Eur. and N. Amer. ; O. eperlanus L., the 

 smelt, sparling, irregular in its migrations, spawning in rivers near 

 high-water mark, generally found in rivers from Aug. to May, spawns 

 about March or April, when fresh exceedingly good eating, but deteriorate 

 in a few hours ; allied genera are Hypomesus and Thaleichthys from the 

 Pacific coast of N. Amer., the latter, known as Oulachan, has so 

 much oil it will burn like a candle ; Mallotus Cuv. ; Coregonus Art. (Argy- 

 rosomtis Ag.), whitefish, mostly lacustrine, a few anadromous, northern 

 parts of temp. Eur., Asia, and N. Amer. ; C. oxyrhynchus L., 

 houting, marine entering f. w. Holland, Germany, Denmark ; C. 

 clupeoides Lac., schelly, f. w. of Lake District and Wales ; C. vande- 

 sius Rich., vendace, f. w. lochs of Scotland ; C. pollan, Thomps., 

 pollan, f. w. of Ireland ; Thymallus Cuv., graylings, clear streams 

 of Eur., Asia, and N. Amer.; Th. vulgaris Nilss., grayling, flesh 

 good, in best condition Oct. and Nov. ; Salanx Cuv. ; deep- 

 sea genera are Argentina, Microstoma, Bathylagus. 



Fam. 13. Stomiatidae. Scales absent or thin ; a hyoid barbel ; eyes 

 large ; luminous spots more or less developed ; no pseudobranch ; ovi- 

 ducts present. Deep-sea fishes descending to the greatest depths and 

 distinguished by their barbel and formidable dentition. Astronesthes 

 Rich., Stomias Cuv., Echiostoma Lowe, Grammatostomias G. and B., 

 Photonectes Gthr., Malacosteus Ayres, Bathyophis, Chauliodus Bloch 

 and Schneider, Bathylaco, Maurolicus, Sternoptyx, etc. 



Fam. 14. Gonorhynehidae, one genus, Aust. and Japanese seas. 



Fam. 15. Cromeriidae, with one genus Cromeria, recently discovered 

 in the White Nile. 



Sub-order 2. OSTARIOPHYSI (CYPRINI SILURIFORMES). 



The anterior vertebrae are co-ossified and have some of their 

 lateral elements detached to form a chain of small bones, the 

 Weberian ossicles, which connect the air-bladder with the ear 

 (p. 202). The air-bladder is probably always present though 



