158 THE VOYAGE OF H.M.S. CHALLENGE!;. 



Species of Hemipholis not herein described. 



Hemipholis cordifera, Lym. (PI. XL. figs. 8-12 ; PI. XLIY. figs. 13-16). 



Hemipholis cordifera, Lym., 111. Cat. Mus. Comp. Zool., No. i. p. 137, pi. i. figs. 1-3, 1865. 



Asterias cordifera, Bosc, Hist. Nat. Vers., vol. ii. p. 138, pi. ii. fig. 3, 1830. 



Uphiura elongata, Say, Journ. Phil. Acad., vol. v. p. 146, 1825. 



Ophiolepis elongata, Mull. & Tr., Syst. Ast., p. 95, 1842; Stimp., Proe. Bost. Soc. Nat. Hist., 



vol. iv. p. 225, 1852. 

 Ophiolepis uncinate, Ayres, Proc. Lost. Soc. Nat. Hist., vol. iv. p. 250, 1852. 

 Hemipholis elongata, Agas., MS. 



Ampliiura elongata, Ltk., Addit. ad Hist., part 2, p. 115, 1859. 

 Amphiura cordifera (Bosc), Ltk., Addit. ad Hist., part 2, p. 120, pi. iii. fig. 2, 1859. 



West Indies. 



Hemipholis gracilis, V1L, Trans. Conn. Acad., vol. i., part 2, p. 2G2, 18(37. 



Hemipholis affinis, Ljn., 0]>h. Viv. Of. Kong. Akad., 1866. 

 Guaj-acpiil. 



Hemipholis microdiscus, Duncan. Journ. Linn. Soc, vol. xiv. p. 4G7, pi. x. figs. 

 20-22, 1879. 



Korean Strait ; 5 1 fathoms. 



Hemipholis wallichii. Duncan, Journ. Linn. Soc, vol. xv. p. 138, pi. vi., is a very 

 young animal, with a disk not more than .5 mm. in diameter. It is not possible to dis- 

 tinguish either the genus or the species. 



Ophiophragmus. 

 Ophiophragmus, Lym., 111. Cat. Mus. Comp. Zool., vol. i., 1865. 



Disk small and delicate, furnished with naked radial shields, and fine overlapping 

 scales ; the scales along the edge of the disk are turned up, so as to make a little fence 

 Teeth. No tooth-papillae. Mouth angles short and small, bearing six close-set little 

 papillae. Arms slender, even and more or less flattened. Arm-spines short and regular. 

 Two genital openings in each interbracliial space. 



It is in the structure of the mouth frames that this genus, as illustrated in Ophio- 

 phragmus wurdemani is peculiar. The upper brachial rims of the contiguous halves 

 form an elevated crescent embracing the outer end of the mouth slit ; while the inter- 

 bracliial rims or wings (PL XL. fig. 4, /) rise as steep crests whose free side (fig. 7) 

 has deep radiating grooves for the attachment of the external mouth frame muscle. 

 Similar, but not at all so large, grooves are found in Ophiocoma, but there is nothing in 

 the character of either genus that seems to call for such a strong attachment. In general 

 build the skeleton is more powerful than that of Amphiura. The radial shields are wide 

 and thick ; the genital plates stout and club-headed, while the arm bones are stouter and 



