NOTES ON THE SALMO SALAR SPECIMEN—MORROW, 167 
producing the beautiful outline of the posterior part of the 
salmon, 
C. 36. On this centrum, (the first of the caudal centra proper), 
the spinous processes are 1 inches in length, and attached pos- 
teriorly for ,; of an inch is a bone or bones having an extreine 
divergence from the normal angle, which might be taken for @ 
pair of ribs. The sp. processes, of which mention has been made, 
are all of the same character as the dorsal and other spinous 
rays, that is formed of two bones, one springing from each side 
.of the arch and united more or less strongly, as the age of the 
fish may be. This bone, or if you choose pair of bones are an- 
chylosed and appear as one, their length from the junction with 
the sp. processes is 2; of an inch; in the skeleton before you the 
separation of their ventral ends is a consequence of their dryness. 
An examination of younger fish will show you that this bone (or 
bones) originates in a different way from the ribs; looking at 
this skeleton of what may be called a mature fish, it appears to 
be a single bone and to have originated and grown from the end 
of the spinous process, passing and uniting with its next posterior 
ventral spinous ray having its ventral end attached to the end of 
the 5rd interspinous fin bone of the anal fin which it slightly over- 
laps, say ; inch on the outer or right hand side. In a young fish 
you will find the spinous processes, but the long bone is merely a 
short straight bone lying between the processes on the 36th and | 
37th centra; in the skeleton of the young fish before you the bone 
does not touch the posterior edge of the 36th sp. process, but is 
about ,, of one inch from it and it just touches the anterior edge 
of the spinous process of the 37th centrum, the end of which it 
does not reach by nearly half an inch; it is therefore most pro- 
bable that it grows from a centre each way, that is dorsally and 
ventrally, but that its growth is most rapid towards its ventral 
extremity. 
C. 37. On this centrum (counting the ribs as sp. processes) the 
35th ventral sp. ray is attached, and is the first ventral sp. ray 
having the usual form; it is 1{ inches in length, its ventral an- 
terior extremity is united by cartilage to the bone just mention- 
ed as springing from the end of the 34th sp. process, the great 
