146 SCOMBRID.€. 



sharp scale, not more than half a line or a millimeter long, and sometimes wholly 

 wanting : the second is a stronger, more decided spine, partly connected behind by 

 a web to the base of the first simple ray of the anal fin. 



In MM. Cuvier and Valenciennes"' figure of G. Prometheus, t. 222, 

 the anal fin is represented larger than the second dorsal ; and there are 

 three detached one-rayed spurious finlets to each, which have no connect- 

 ing web. 



Pectoral fins rather small and weak, oblong or subtrapeziform, and obliquely 

 truncate. They are placed at about one third of the height up the side, close 

 behind the edge of the opercle ; and are about one eighth of the whole length of 

 the fish. 



Ventral fins reduced in the adult fish to two minute, short, and blunt scale-like 

 stumps or warts, almost buried in the skin, placed close together on the abdominal 

 line a little before a line drawn vertically through the fore axil of the pectoral fins. 

 But when the fish is very young, each consists of a single, straight, rough, sharp, 

 and pretty strong spiny ray, which is rather longer than the pectoral fins, its tip 

 reaching back as far as theirs m situ, though its base is situate a little forwarder 

 than theirs : and in this case there is no trace of web or of other rays. Thus it 

 appears that the short scale-like ventrals of the adult fish are the worn or broken- 

 down stumps only of these spines in the young. This mutilation appears to take 

 place constantly and very early. The single example in which I found the ventral 

 spines thus perfect, was five inches and three eighths long : MM. Cuvier and 

 Valenciennes' G. PrometheKs was only ten inches long, and yet the ventral fins 

 were " infinitely small : " there was moreover " beside the spine some trace of 

 soft ray ; " which I also find to be the case in adult fishes. 



It would be interesting to discover what peculiarity in the habits of this 

 fish leads to this regular and early mutilation : for in some allied fishes 

 (Histiophorus and Tetrapturus) in which the ventral fins are reduced to a 

 similar single and even much longer and more slender ray, no such effect 

 takes place. The mere absence of the groove which protects them in 

 Histiophorus^ will not entirely account for this. It is, however, perhaps 

 partly explained by the consideration that the Coelho is wholly a ground or 

 bottom fish ; whilst Tetrapturus is a surface or pelagic one. 



The caudal fin is forked ; its lobes are rather broad and short : the upper 

 being a little the longest. It is from one sixth to one seventh of the whole 

 length. 



At first with the exception of the lateral line, the whole fish appears quite 

 smooth and naked, or devoid of scales. But examined more closely, the opercles, 

 cheeks, body, second dorsal, anal, and caudal fins are found to be minutely, though 

 to the unassisted eye obscurely scaled : the scales being small and close-pressed, 

 very soft, thin, or membranous, smooth, and deciduous ; varying in shape from 

 round to oval. 



The lateral line begins very high up, at the junction of the opercle with the 

 body, on the nape ; and running straight a little way, makes an abrupt oblique 

 descent about the middle of the pectoral fins ; continuing in a straight line below 

 the middle of the sides from their tips to the root of tlie caudal fin. It is some- 

 what raised and very distinct throughout : narrower, but not more tumid towards 



