VOL. LXXI.] PHILOSOPHICAL TRANSACTIONS. 137 



triangular and sharp apophysis, to which adheres a ligament as to the 2d. The 

 4th is remarkable in having a sharp apophysis on each side, articulated with the 

 body of the vertebra, and under each of them is another articulated apophysis, 

 flattish, thick, roundish at its extremities, and forked at its basis (fig. 5.) The 

 5th, which is strongly adherent to the former, has in its middle a bifid process. 

 The 6th has in its middle a flattish elevation, sharp on each side. Between the 

 extremity of the larger apophysis of the 4th vertebra, is a bone, or rather a hard 

 cartilage, which bears the figure of a kidney (fig. 6) ; its convexity being turned 

 towards the body of the vertebra : its position is parallel to the bodies of the 

 vertebrae ; its motion is half circular ; one of its parts, viz. the lowest, being in 

 the cavity of the swimming bladder, to which it adheres by a thin membrane, so 

 that no air can escape at that part. It is covered by membranes, which adhere 

 strongly to its middle ; in this part are fastened the 2 ligaments of the apophy- 

 sis of the 2d and 3d vertebrae, of which we spoke before, and which are of a 

 greater tenuity. In the same point are fastened also 2 ligaments; each of which 

 belongs to an oblong muscle parallel to each other, and fixed to the bones of the 

 lowest and posterior part of the head (fig. 4.) 



All this apparatus is certainly subservient to the purpose of swimming, I sup- 

 pose, by the cavity of the bladder being made larger or less by the motions of 

 the cartilaginous bone; but it is very remarkable, that if these parts are neces- 

 sary to some animal function, they should not be found in all the individuals ; for 

 I have seen 2, of which the vertebrae were not different from the vertebrae of 

 the other species : which difference depends perhaps on the difference of sex. I 

 am inclined to believe so ; but the generation in this fish seems to be no less 

 mysterious than that of the eel : I could never distinguish a male from a female 

 in this species. I do not know if the other species of ophidium have the same 

 structure ; I could not perceive it in some specimens of mastacembelus. Wil- 

 loughby mentions that singular structure, but without any particular description. 



This fish commonly grows to the size of 8 or 9 inches. It is to be found in 

 all the Mediterranean Sea, and in great plenty in the Adriatic. It is taken by 

 nets in Provence and Languedoc, with many other small species, which are not 

 esteemed, that is, what they call ravailla. It is often confounded with the cepola 

 by the fishermen, though they have different names for each species. In Lan- 

 guedoc the ophidium is called donzella, and the cepola, flamma. In Provence 

 the former has the name of corrudgiao, and the latter that of rougeolla. But 

 the name of donzelli, very common on all the coast of the Mediterranean, is 

 also applied to the cepola, and the sparus julisLinn. which however is commonly 

 called girella. In summer the ophidium is more common : its flesh is not of a 

 good taste, rather coarse, as that of all the species of fishes, which having no 

 ventral fins, are obliged to make great efforts in swimming, and have conse- 



vol. xv. T 



