External Embryonic Development of Chlaynydoselachus 581 



Early Development 582 



Blastulae 582 



GASTRin.AE 588 



Later Development 590 



Resume of Researches on the Internal Development 591 



Descriptions of Embryos Figured 592 



An Embryo of 11.5 Millimeters 593 



An Embryo 15.5 mm. in Length 594 



An Embryo Measuring 20 MaLiMETERS 595 



Two 25-MM. Embryos — Heads Only — Described by Ziegler and Brohmer 596 



Nishik.mi'a's 32'MM. Embryo — Head Only 598 



Dean's Embryo, 34 mm. in Length 603 



An Embryo of 39 Millimeters 601 



The 39-mm. Embryo and its Yolk Sac dj Color 602 



Nishikawa's 43'Mm. Embryo ok its Yolk S.^c 603 



Dean's Embryo of 46 millimeters 603 



Head of a 48'MM. Specimen in Ventral View 605 



Nishikawa's 50'MM. Embryo on its Yolk S.ac 605 



An Embryo of 54 Millimeters 607 



An Embryo Me.-\suring 55 Millimeters 608 



Carman's Embryo of 64 MaLiMETERs 609 



Dean's Embryo Measuring 66 MaLiMETERs 610 



An Embryo 103 mm. in Length 612 



An Embryo of 124 millimeters 612 



An Embryo of 175 mm. and its Yolk Sac 613 



An Embryo 185 mm. in Length 614 



A Young Frilled Shark 240 mm. Long '. 615 



A 390'MM. Chlamydoselachus IN N.atural Colors 615 



THE YOLK SAC CIRCULATION 61? 



Vitelline Circulation of the 39'MM. Embryo 618 



YoLK-S.*c Circulation of the 43-mm. Specimen 619 



Vitelline Circlt-ation of the 50'mm. Embryo 621 



Yolk-Sac Circl'lation of the 175'Mii. Fish 621 



Vitelline Circulation of the 390'MM. Shark 621 



The Adult Chlamydoselachus 622 



An Adult Female Frilled Shark 622 



An Adult Male ChlamydoseJachus 624 



He.AlD Only of the Adult Shark 625 



He.'^d — Dorsal View 625 



Head — Ventr.-\l Aspect 625 



External Gill'Filaments of Chlamydoselachus 626 



External Gill-filaments of the Embryo 626 



External Gill-filaments of the Adult Frilled Shark 629 



Bibliography 631 



'524 



