. Chimæroid fishes and their development. Fishes; Chimaeridae. Fig. 1 12.—Ventral fin and appendages in Chimaera coiliei. A. Fin of young specimen (31 cm. in length) : venual aspect showing mixipterygia and antero-ventral clasper, the latter still connected by derma! crease with the anterior rim of fin; t', mixiplerygium with lips unfolded ; B, skeleton of foregoing fin. showing the arrangement of the supports (radials) of the branches of the mixiplerygium ; C, skeleton of fin. adult; D. skeleton of ventral fin of Cestracion (Heterodontus japonicus), adult, for comparison with foregoing. pelvi
. Chimæroid fishes and their development. Fishes; Chimaeridae. Fig. 1 12.—Ventral fin and appendages in Chimaera coiliei. A. Fin of young specimen (31 cm. in length) : venual aspect showing mixipterygia and antero-ventral clasper, the latter still connected by derma! crease with the anterior rim of fin; t', mixiplerygium with lips unfolded ; B, skeleton of foregoing fin. showing the arrangement of the supports (radials) of the branches of the mixiplerygium ; C, skeleton of fin. adult; D. skeleton of ventral fin of Cestracion (Heterodontus japonicus), adult, for comparison with foregoing. pelvic fin there formerh' existed a number of radialia ; witness, for example, the rudiments of the segmentation of the basal plate from which the antero-ventral organ arises (fig. 112, nerve and vessel openings in b and c),t or better still, the radials which persist in the anterior reach of the fin of the Jurassic Chimseroid, Squaloraja (fig. 138, ar). The mixipterygium also bears testimony to having been closely connected with the radials of the base of the fin; thus in one stage in development, cf. fig. 112 b, the base of the mixipterygium bears rudiments of radialia, and the trifid tip is in itself a relic of a clustering of distal radials. These observations are clearly in line with Jungersen's, who, while admitting that the "appendix-skeleton of the Holocephales is of less compound construction than that of Plagiostomes," calls attention to the "wide separation of the whole organ {i. c.,) * In the adult Chimseroid the basal articular element of the pectoral fin is usually termed (as in Cestracion) mesopterygium, audit is regarded (Gegenbaur, igoi) as including also the propterygium; Schauinsland, however, has shown {o-p. cit., Taf. xxiv, fig. 174) that the bibasal character of the fin is due to the obsolescence of the metapterygium. The articular basal is, therefore, the propterygium. With this result the present writer is in accord. fXhis conclusion was ori
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1906
