OPHIUROIDEA OF THE BAHAMA EXPEDITION. 65 



Family, OPHIOMYXID^E Ljung. (restr.) , 1866. 



Ophioscolecidce (pars) Lutk., 1869. 



Ophiomyxince (sub-family) Ejung., 1871. 



Ophiomyxidce Carus, Fauns Medit., p. 96, 1884. 



Disk and arms covered with thick cuticle, and usually with 

 only a row of marginal disk-scales, and a few scattered ones 

 imbedded in the cuticle, but visible only when dried. Radial 

 shields small, usually with a proximai series of small supple- 

 mentary scales. 



Teeth and mouth-papillae stout, flat, with the end serrated. 

 No tooth-papillae. True tentacle-scales generally absent. 

 Under arm-plates small. Side arm-plates sub-ventral, bear- 

 ing several rough divergent spines. Upper arm-plates rudi- 

 mentary or lacking; when present, composed of small pieces. 

 Two large, triangular, peristomial plates on each mouth- 

 angle. 



Arm-bones peculiar, belonging to the modified "hour-glass- 

 shaped" type; with well-formed condyles on both ends. 



Ophiomyxa is the only genus described, but it evidently in- 

 cludes two generic groups. The second genus has the fol- 

 lowing characters: 



Ophiodera, gen. nov. Type, O. serpentaria (Lym.) 



Marginal disk-scales, are rudimentary, and the disk-scales 

 proximal to the radial shields are lacking. No upper arm- 

 plates. Side arm-plates may be soldered to the under arm- 

 plates; they are not contined upward by a row of supple- 

 mentary plates. Three arm-spines, enclosed by cuticle. 



Ophiomyxa flaccida (Say) Lutk. 



Ophiura flaccida Say, Journ. Phil. Acad. Nat. Sci., V, p. 151, 1825. 



Ophiomyxa caribcea Eutken, Vid. Meddel., p. 10, 1856. 



Ophiomyxa flaccida Eiitken, Add. ad. Hist. Ophiur., Pt. II, p. 138, pi. 

 V, fig. 1, 1859. 



Ophiomyxa flaccida Lyman, 111. Cat. Mus. Comp. Zool., I, p. 178, pi. II, 

 figs. 18, 19. Verill, Trans. Conn. Acad., I, Pt. II, p. 341, 366, 1868. 



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