1^68.] DEVELOPMENT OF THE SALMON. 2.")3 



nearly equal size, I have placed alongside the dimensions of two 

 specimens in the British-Museum collection. 



Unfortunately for perfect exactness of corresponding measure- 

 ments, mine have been taken in tenths of an inch, while Dr. Gunther's 

 are sixteenths, eighths, and quarters of an inch. Notvrithstanding 

 this difference in fractions, tiie eye is able to follow the lines of re- 

 semblance, or otherwise. 



Specimens in 

 British Museum. 

 No. 1. a. I,. 



Total length G-.i fJi 7h, 



Length of the head 1-4 |1l^ 1 Ts-^ 



Distance between end of snout and eye 03 4 if 



Diameter of the eye " o.s . . 4- 



Length of maxillary bone 0"6 -**. i 



Length of base of dorsal 0'9 



Greatest height of dorsal 1-2 



Length of pectoral 1 -2 



Distance between root of pectoral and root of 



ventral l-G 



Length of ventral fin 3-1 



Distance between root of ventral and origin of 



anal fin 1-2 



Length of anal fin 0'8 



As regards the internal anatomy of the specimen No. 1, of which 

 the bodily measurements are given above, the following points were 

 noted:— -The caecal tubes were from 48 to 50 in number; I state 

 both of these numbers because, although counted several times, there 

 was difficulty, 49 being counted once, 48 a second time, and 50 a 

 third. They were small and not well developed ; greatest length of 

 a single one O'S inch. The intestine beyond the cEcci measured 

 barely 3 inches long. Testes moderately developed, 2| inches long, 

 milt flowed freely on being handled. Air-bladder large" long, single, 

 and tapering behind. The vertebrae are 59 in number. 



After having described our specimen, it still remains to say whether 

 it is a Salmon or not. If not a true Salmo salar, then one would 

 expect it be some other well-known form of the genus Salmo. 



Now upon this point there is some diversity of opinion. Mr. 

 Buckland and Mr. Bartlett aver it is, and that th'e whole of the brood 

 which I have referred to as having been hatched in February 1863 

 are true Salmon. This view I have been myself inclined to adopt ; 

 but the opinion of Dr. Gunther, than whom I know not a more' 

 scientific ichthyologist, has in some respects made me waver respect- 

 ing a decision. On the other hand, it has strengthened my belief 

 that the arrest of the growth of Salmon when retained in fresh water 

 is a physiological fact, perfectly compatible with what we already 

 know connected with the life-development of the Salmon. 



Those who have regarded our specimens as Salmon have done 

 so, first, because of tiieir history; secondly, from their external 

 markings and other outward anatomical resemblances to Salmon ■ 



