LIMBS. 



61; 



The pectoral fin. The earliest stage of the pectoral fin 



/n. (> 



FIG. 347. PELVIC FIN OF A YOUNG MALE EMBRYO OF SCYLLIUM STELLARE. 



bp. basipterygium ; in.o. process of basipterygium continued into clasper; il. iliac 

 process of pectoral girdle ; pit. pubis. 



differs from that of the pelvic fin only in minor points. There 



is the same longitudinal 



or basipterygial bar to 



which the fin-rays are 



attached, whose position 



at the base of the fin is 



clearly seen in the trans- 



verse section (fig. 346, 



nipt}. In front the bar is 



continuous with the pec- 



toral girdle (figs. 344 and 



348). ^ 



The changes which 

 take place in the course of 

 the further development 

 are however very much 

 more considerable in the 

 case of the pectoral than 

 in that of the pelvic fin. 



By the process spoken 



FlG - 34- 



PECTORAL FIN OF AN EMBRYO OF 

 SCYLLIUM STELLARE. 



nip. metapterygium (basipterygium of earlier 

 stage); inc. p. rudiment of future pro- and meso- 

 pterygium ; sc. cut surface of scapular process ; 



of above, by which the 



attachment of the pec- [/-. c "oracoid process;//-, foramen;/ horny fibres.' 



