52 PHYSOSTOMI. 



Family II SALMONIDJE, Midler. 



Pseudobranchise present. Margin of the upper jaw formed by the premaxillaries 

 and maxillaries. No barbels. Anteriorly a rayed dorsal fin, and posteriorly an 

 adipose one. Pyloric appendages as a rule present, and usually numerous. Body 

 scaled. Head scaleless. Air-bladder large, simple, and with a pneumatic duct. 

 The ova pass into the cavity of the abdomen before being extruded. 



Geographical distribution. Marine and freshwater forms, some of the former 

 being exclusively inhabitants of the deep sea, others again being anadromons, 

 periodically ascending rivers in order to deposit their spawn. Normally they are 

 confined to the Arctic and temperate portions of the northern hemisphere, with the 

 exception of one species which has been found existing in New Zealand. Some 

 of the genera among the salmonoids furnish most valuable food to the human race r 

 consequently it has been an object to extend their range into the waters of distant 

 lands. In introducing exotic fishes, one of the first considerations must necessarily 

 be to ascertain whether any representatives of the family are normally resident in 

 the region it is desired to stock, and if they are whether the race is a thriving or 

 a diminutive one ; for it has been maintained that if the latter the chances of 

 success are too small to render the attempt worth making, as the region is probably 

 unsuited for their development. By retarding the germination of the ova by 

 means of ice (see Introduction), eggs of salmonidse have been safely carried to 

 Tasmania and elsewhere, and the races successfully introduced. In 1866 I 

 attempted to similarly convey trout into the waters of the table lands on the 

 Neilgherries and adjacent hills in Madras. These mountain ranges embrace a 

 geographical area extending over 268,494 square miles : their peaks vary from 

 5000 to 8000 feet above the sea, and Ootacamund, where the experiment was tried, 

 is 7426 feet above the sea-level, with an annual mean temperature of 58 68'. 

 Although I failed, two years subsequently Mr. Mclvor succeeded by bringing out 

 the young fish from Scotland, and they have bred in their new home, enabling me 

 to give a figure in the third part of my Fishes of India, published August, 1877, 

 taken from an Indian born trout.* 



Synopsis of Genera. 



1. Sahno. Maxillary long : dentition strong and complete. Scales small. Anal 

 rays in moderate numbers (14 or less). Pyloric appendages numerous. 



2. Osmerus. Maxillary long : dentition complete, with fang-like teeth on the 

 vomer and tongue. Scales of medium size. Pyloric appendages few. 



3. Coregonus. Maxillary short : teeth if present minute. Anterior dorsal fin 

 with few rays. Scales of moderate size. Pyloric appendages numerous. 



4. Thymallus. Maxillary short : small teeth in the jaws, vomer, and on the 

 palatine bones. Anterior dorsal fin many rayed. Scales of moderate size. Pyloric 

 appendages numerous. 



5. Argentina. Maxillary short: teeth absent from jaws. Anterior dorsal fin with 

 few rays. Scales rather large. Pyloric appendages few or in moderate numbers. 



* On recording; my first failure. Dr. Giinther as editor of the Zoological Kecord, remarked, 

 as " has been foreseen by all acquainted with the nature of salnionoid fishes." And since it succeeded, 

 in his "Introduction to the Study of Fishes," 1880, p. 641, he has observed "the attempt of 

 transferring them into the low streams of India ended (as could be foreseen) in a total failure." 



