1910.] CAUDAL FIX OF TUE TELEOSTOMI. 625 



13. Gregouv, W. K.— "The Orders of Teleostomoiis Fislios." 



Annals New York Acad. Sci. vol. xvii. pt. ii. no. 3, l',)()7. 



14. Huxley, T. H. — " Ou some parts of the Skeleton of Fishes." 



Quart. Journ. Micro. Science, 1859. 



15. KoLLiKER, A. — Ueber das Ende der Wirhelsiiule der 



Ganoiden und einiger Teleostier. Leipzig, 1860. 



16. Loxz, T. — "Ueber den Ban der KSchwanzwirbelsaule der 



Salmoniden, ii. s. w." Zeit. flir Wisson. Zoologie, 14, 1864. 



17. McCoy, F.— Annals .t Mag. Nat. Hist., 1848. 



18. Newton, E. T.—" Fishes' Tails." Jour. Quekett Micros. 



Club, vol. i. sei'ies ii., p. 79, July 1882. 



19. Regan, C. T. — " On the systematic position of the Gadoid 



or Anacanthine Fishes." Ann. & Mag. Nat. Hist. xi. 



20. " Remarks on Cnidoglanis megastomi." Proc. Zool. 



Soc, April 28th, 1908. 



21. Ryder, J. A. " Evolution of the Fins of Fishes." Rep. of 



the Oamm. of Fish &, Fisheries, Washington, 1884, pub- 

 lished 1886. 



22. Wiiitehouse, R. H. "The Caudal Fin of Fishes," Pre- 



liminary Paper. Pi^oc. Royal Society, B, vol. 82, 1910. 



Reference Lettering. 



B.D Basi-dorsal. 



c Cartilage supporting fin-raj's. 



d Distal segment of radial. 



d.c.r Dorsal caudal radial. 



der Dermotricliia. 



e.h Ensheathiug' bone protecting notochord. 



ep Epural. 



/ Fulcra. 



h Hyatus between dorsal and ventral rays. 



h.a Hittnial arch. 



/)(/ Hypural. 



I'.D Inter-dorsal. 



l.v Last vertebra or centrum. 



m Median segment of radial. 



n Notochord. 



n.a Neural arch. 



n.a.^ Probably a neural arch protecting end of spinal cord. 



n.s Neural spine. 



ox Opisthural cartilage. 



p Proximal segment of radial. 



p.o Penultimate vertebra or centrum. 



s Secondarily developed bon^' sheath protecting the 



spinal cord. 



sp.c Spinal cord. 



nr Urostyle. 



v.c.r Ventral caudal radial. 



EXPLANATION OP THfi PLATES. 



Plate XLVII. 



Fig. 1. Caudal fin of Heterodnntus pJiillippi. Illustrating a typical Elasmobraneh 

 hetcrocercal caudal fin. At the anterior end of tiie ventral lobe will be 

 seen two radials {L'.c.r.) quite distinct from the hwmal arches. Dorsally, 

 at the anterior end of the fin, the radials are' well separated from the 

 neural arches. The proximal ends of the horny" fibres have, throughout 

 the fin, been removed in order to expose the endoskeletal supportb. 



