THE SEA-SCORPION-FAMILY. 127 



bulk, and a series of sharp spines project from the gill-cover, 

 and two on each side of the occiput. The larval tail is present, 

 but it is bent upward by the development of the true rays 

 inferiorly. The ventral fins appear as minute processes. 



In contrasting such a stage (e.g., one 9 mm. in length) with 

 a gadoid, it is easily distinguished from the latter by its shorter 

 snout, smaller mouth, and smaller eye, as well as by the deeper 

 greenish pigment, with a trace of yellow on the head and 

 abdomen. Moreover, the latter is much more densely and 

 somewhat regularly spotted with blackish pigment, the whole 

 having a tessellated aspect. Further, from the greater tenacity 

 of life in the sea-scorpion, the body does not so soon assume the 

 whitish opacity so characteristic of the gadoids ; indeed, though 

 perfectly motionless, the heart may be pulsating. The blackish 

 pigment again is confined to the ventral edge instead of passing 

 along both dorsal and ventral edges, as well as some distance up 

 the sides, as in the gadoids. 



Except in the tail, the young gadoid of the same size has 

 only embryonic rays in the continuous marginal fin, while in 

 the sea-scorpion a considerable number of rudimentary true 

 rays occur both dorsally and ventrally (10 or 11 dorsally and 

 6 ventrally). In the anal fin the true rays commence anteriorly. 

 Those in the dorsal begin just above the latter (that is, a little 

 behind a perpendicular line from the vent). No permanent 

 rays appear in the dorsal and the ventral marginal fin of the 

 gadoid, even though the example exceeds in length the cottoid 

 of this stage. 



A very evident difference exists in the tail of those of equal 

 length. Thus, the upper and lower elements (epiural and 

 hypural) are more or less equally developed in the gadoids ; 

 the ventral series, however, terminating in one or two larger 

 cartilages. The tapering notochord (elementary back-bone) is 

 straight, and extends considerably beyond both series. True 

 caudal fin-rays, moreover, are developing both dorsally and 

 ventrally, giving the tail a peculiarly symmetrical or 'feathered' 

 appearance. 



On the other hand, the notochord in the sea-scorpion is 

 somewhat less finely tapered, has a thicker sheath, and the 



