&2 SUPPLEMENT ON 



adhere to only one vertebra. They bear often in an appen- 

 dant form, adhering to some part of their length, one or two 

 styli (No. 73, 73), which are directed outwards, and penetrate 

 between the fleshy parts. It is in this manner the fine bones 

 are multiplied, such as we see them in herrings. The ribs, 

 not being employed in respiration, are little moveable ; in 

 some cases they encircle the whole abdomen, others have 

 scarcely rudiments of ribs, and there are a few which are 

 totally deprived of them. 



The vertical fins have each ray composed of an internal 

 part, named inter spinous (No. 74, 74), which penetrates into 

 the fish between the great lateral muscles, and forms the 

 fixed part ; and of an external part (No. 75, 75), which is the 

 fin itself. There are often interspinous bones (No. 76), which 

 bear no rays, and sometimes others bearing more than one. 

 The interspinous usually have their points directed between 

 the spinous processes of the vertebras. The vertical rays 

 (No. 75, 75) articulate by a lax ginglymus, each upon its 

 interspinous bonelet, which enables them to be raised or 

 depressed at pleasure. Some of these rays are pointed bones 

 named spinous rays ; others are bony at the base, but the rest 

 is composed of a number of small articulations, very often 

 ramified into other branches : these are named articulated, 

 soft, and branched rays. Those of the tail are always of this 

 last description (No. 71), but at the root above and below 

 there are small bones (No. 78, 78), diminishing in size 

 towards the front, where no part of them remains except their 

 solid base. There is in general one ray less on the inferior 

 half of the tail fin. In a great number of fish, the first and 

 often the second post abdominal vertebra (No. 83, 83) have 

 large inferior spinous processes, to which a bone is joined 

 (No. 79), extending to behind the anus, and thus forming 

 the posterior boundary of the abdominal cavity. The fore- 

 most interspinous bones, both above and below in certain 



