142 



SCANDIXAVIAN FISHES. 



way in imniber and length, though they never ;itt;iin 

 so great a length as the rays of the ventral tins. 

 For a time all the last four rays in this tin are united 

 liy a membrane at the Ijase (tig. 38, h), until at 

 last the first ray appears just in front of the second 

 and above the middle of the eye, being thus some 

 distance from its future place on the snout, although 

 the whole anterior part of the tin has advanced con- 



first rudiment of which appears on the ventral side of 

 the notochord (fig. .38, a, +) in the form of two carti- 

 laginous disks lying below the notochord in the mesial 

 line of the body, the one in front of the other, just in 

 front of the boundarj' of the pigment collected on the 

 rudimentary, rod-like rays in the fin-membrane round 

 the end of the tail. During the subsecjuent develop- 

 ment of the tin these cartilaginous disks force the end 



Fig. 39. Young l^upluus piscatoiius from the Mc-diteiraneau off Messina. After KiTPELL and Ginther. 





Fig. 40. Young Lophiiis jiixcatoriiis (=LnpIi. euryptcrus) from Cliristiansunii (Norway). Natiir.al size. After v. DOben and Koren. 



a: seen from above; h: seen from tlic left. 



siderabh- from its original situation. The Hat dermal 

 flaps, the rudiments of the pectoral fins, have steadily 

 grown, and been furnished M'ith a greater number of 

 rays; but even in the last stage examined by Aoassiz 

 (fig. 38, c) the tips of these rays are not yet free. Last 

 of all appear the second dorsal and the anal fins, which 

 occupy tiicir ulliuiate situation and mutual ])osition 

 pr(!tty closely from the lirst, and the caudal fin, the 



of the notochord upwards; and at their lower margin, 

 which e\entually becomes the hind margin of the tail 

 (the hypural bones), the future rays of the caudal fin 

 begin to appear (fig. 38, h). This is the usual course 

 of development of the caudal fin in the osseous fishes, the 

 caudal fin of which is thus originally ventral, like the 

 greater (lo^ver) pai-f of the caudal fin in the heterocercal 

 fishes, and is, strictly speaking, to be assigned to the same 



