SORTAT10N. 41 



Yet another key the last of the bunch 

 Ventrals abdominal 

 Barbules 6 



Erectile spine under eye Cobitis 

 No spine under eye Netnachilus 



Barbules 4 



Dorsal with 22 rays Cyprinus. 

 Dorsal with n rays Barbus. 



Barbules 2 



Anal 8 rays; ventrals 8 rays Gobio. 

 Anal 9 rays ; ventrals 10 rays Tinea. 



No barbules 



Abdomen rounded all along 

 Dorsal placed far back Esox. 



Dorsal placed midway 



Anal with 5 to 7 rays Carassius. 

 Anal with 8 to n rays Leuciscus t 



Abdomen rounded in front of ventrals and compressed 



behind them 

 Dorsal with spine Abramis. 

 Dorsal without spine Alburnus- 



Abdomen compressed all along 

 Upper jaw projecting Engraulis. 

 Upper jaw not projecting Clupea. 



Externals have served our purpose of identification, but, when we 

 come to classification and zoological order, recourse to internals is 

 inevitable. A few notes on structure we cannot do without, but we 

 need not in this little book, written for the special purpose of merely 

 ascertaining the name of the fish, have more notes than are 

 necessary for understanding the descriptions that follow. The 

 anatomy of the fishes is not a simple subject; some species have a 

 thousand separate bones, and some sharks have quite as many 

 vertebrae as there are days in the year, though the vertebras of the 

 bony fishes range from only 14 (in Batistes) to as many as 200. 



The vertebra of a fish that is, one of the sections of which the 

 backbone is built up is, as is well known, hollow at both ends, or, 

 to be correct, it is so in all British fishes. For descriptive pur- 

 poses, the vertebrae are divided into those that are abdominal and 

 those that are caudal, the former being in the front of the body and 

 carrying the ribs by means of the transverse processes one on each 

 side. From the top of all rise two " neurapophyses," which carry a 

 neural spine, the arch formed by these at their bases being the 

 neural arch, through which runs the spinal cord. From the bottom 

 of the caudal vertebrae issue " haemapophyses," of much the same 

 shape, which, at their bases, form the haemal arch and at their tips 

 carry a haemal spine. Some exceptionally all of the neural spines 

 are the supports of the " interneurals," with which the spines and 

 rays of the dorsal fin articulate, and the haemal spines carry the 

 " interhaemals," which are connected with the spines and rays of 



