FISHES. 291 



instance of this is seen in the Polyprion.* The cyprins have something 

 more particular in three small bones, placed between those of the jaw 

 and cranium, of which we shall speak in another place. 



The form of the snout in fishes depends generally on that of the 

 intermaxillaries, sometimes flat horizontally, or compressed on the 

 sides ; sometimes obtuse or rounded; sometimes advanced beyond the 

 mouth, presenting a prominence more or less salient, and sometimes 

 even enormous, as in the xiphias ; sometimes prolonged with the 

 lower jaw to a sort of beak, as in the gar fish. It is more particularly 

 on the length of these ascending pedicles, and of the intermaxillaries, 

 that the greater or less protractibility of the mouth depends, that is, of 

 the power which the fish possesses of projecting it suddenly beyond the 

 snout ; but all these circumstances, of which we speak, when treating 

 of each kind, have no influence on the composition of these parts. 



The Nasal, Suborbital- and Super temp oral Bones. 



The nasal, suborbital' and supertemporal apparatus in fishes varies 

 the most, as to the number of pieces composing it. The first subor- 

 bitar (No. 19,) the boldest in general as to form articulates with a 

 facet of the inferior external apophysis of the anterior frontal; a cir- 

 cumstance which might cause it to be regarded as analogous to the 

 lachrymal, f It forms the external or inferior border of the cavity of 

 the nostril, whilst the internal or superior border is formed by the 

 nasal (No. 20,)|. which articulating above with the frontal (No. 1,) 

 descends along the anterior ridge of the ethmoid (No. 3,) and with its 

 inferior part sometimes covers the junction of the palatine (No. 22) 

 with the maxillary (No. 18), and of the maxillary with the intermax- 

 illary (No. 17.) To this first suborbital - (No. 19) is united a chain 

 of bones, varying in size and number (No. 19,) || which terminates 

 in an attachment to the posterior frontal (No. 4) after surrounding 

 the inferior half of the orbit. At most this chain of small bones 

 might be said to represent that portion of the jugal bone, which occu- 

 pies the same situation in a great number of animals ; it even some- 

 times happens that a part of these bones gives off a lamina, which 

 passing under the orbit, forms an incomplete roof. These bones 

 constitute a cuirass for the jaw, the crotaphite, and the neighbouring 

 muscles in certain fishes, the gurnards, the scorpens, certain sal- 

 mons, &c, ; other small bones are not unfrequently found in their 

 suite, forming a similar chain behind on each side (No. 21) between 

 the external apophysis and the intermediate apophysis of the cranium, 

 and covering the articulation of the superscapulary bone (No. 46), 



* It is this apophysis thus separated that Mr. Geoffroy takes for the inferior 

 horn of the nose, and which he calls rhinosphenal. 



-f- This is the adorbital or orbitary portion of the maxillary of M. Geoffroy, M. M. 

 Spix, Bojanus, Bakker, and Meckel refer it, as well as the succeeding ones, to the 

 jugal. M. Carus to the lachrymal. I am induced to consider this apparatus as dif- 

 fering from th*ose of other vertebrae, on account of its covering the muscles, instead 

 of giving attachment to them. 



X This is the ethmophysal or superior horn of the nose of M. Geoffroy. 



|| These are the jugals of M. Geoffroy. 



u2 



