HSUKJ-. , 307 



arm, which are elongated and form at the surface certain kinds ol 

 arms, in the genus lophius where there arc only two, in that of 

 batrachus where there are five, and in the polypterae where there are 

 only three.* Under these circumstances the ulna and radius are very 



much reduced. 



Bones of the Posterior Extremity. 



The os innominatum, the thigh, the leg, and the tarsus on each side, 

 lire represented by merely a single bone (No. SO), generally of the 

 form of a triangle, but more or less complicated with apophyses and 

 protruding layers. j- The apex of the triangle is heiore, and in the 

 ftsb.es denominated by Linnseus jugular and thoracic 1 , that is to say. 

 in my Subbrachians, this apex or the apophysis which replaces it, are 

 attached to the symphyses of the bones, which we have called hume- 

 rus. In the true abdominal fishes it remains free in the flesh. 



The posterior side, which is usually the narrowest, gives attach- 

 ment to the rays of the ventral fin, to the internal side of which rays 

 it often gives another apophysis behind (b b). Almost always the 

 internal side is united to that of the corresponding bone by suture 

 (a a). Sometimes it happens that these two hones remain sepa- 

 rated from each other, either before as in the genus lophius, or 

 behind as in that of batrachus. Every hody is acquainted with the 

 fact that very many fishes, such as the eels, the electrical eels, the 

 sword-fishes, &C, are utterly destitute of ventral fins, while others, as 

 the lepidopus, are furnished only with very imperfect traces of these 

 fins. In the former case there is no vestige whatever of a pelvic 

 hone. 



The Rays of the Extremities. 



The rays of the extremities without being so symmetrical as those 

 of the vertical fins, are divided in the same longitudinal direction, 

 each into halves. They are almost always, the whole of them, arti- 

 culated, with tin 1 exception of the external ray of the ventral in the 

 aoanthopterygians, but their base is more compact than the remaining 

 part of their length, and the articulations are invisible or nearly so. 

 This base is increased in such a manner as that it is able to form a 

 solid attachment to the bones of the radius, of the carpus, and of the 



* M. Geoffroy (loc. cit.) has supposed that the two long bones which sustain the 

 pectoral in lophius, are the bones which lie calls radius and ulna in other fishes; but 

 this is certainly not the case ; tin' two bones which we consider as the bones of the 

 lore arm, are found in their natural situation in this genus as in all others, ami the 

 two great bones, which form the pedicle of the tin, are Bome of those which we refer 

 to the carpus. At. Bakker adopts the idea of M. Geoffrey; lie lias adequate^ 

 estimated the difficulty, but has been unable to solve it. M. Meckel considers this 

 bone preciselyas we do. In the bichers (polypterus) there are three bones which 

 are lengthened out to support the pectoral, and the pieces of the base of the rays 



form, in these animals, a second low to this description of e opus. M. Ceollioy 

 has taken the two extremities of these three boms of ihe carpus, fur the radius and 

 ulna. The same bones are lengthened in the plat yeephalus, periophtalmus, and 

 other genera, in which it is impossible not, to distinguish the bones of the arm 

 before the latter. 



f M. Bakker calls this coxa. It is represented plate HI, fur. 8 bj the superior 

 , and fig. 9, by the inferior. 



X J 



