A. E. Verrill — North American Ophinroidea. 363 



tentacle-pore. It is often reduced to a minute si:)inule, and is fre- 

 quently absent. 



Arm-spines three or four, divaricate, small, nearly equal, sharp, 

 roughly serrulate and glassy, more or less covered by cuticle when 

 in alcohol. 



The internal arm-plates show as transversely rhombic plates sepa- 

 rated by wider intervals. 



Family, HEMIEURYALID-ffi Ver., Opli. Bahama Exped. , p. 70, 1899. 



In this family are included several genera of true Ophiurae, which 

 very much resemble, in form and habits, the simple-armed Euryalse 

 or Astrophytons. Like the latter, they coil their arras closely 

 around the branches of gorgonian corals on which they dwell. 



The disk is pentagonal and covered with thick plates or tubercles, 

 which may be conical. The radial shields are large and prominent. 



Upper arm-plates may be entire and accompanied by supplemen- 

 tary plates, or they may be replaced by a mosaic of small plates. 

 They are thick or tubercular. 



Under arm-plates well formed. Side-plates separated by extra 

 plates. Oral and adoral shields normal. Spines few, short and 

 stumpy. A row of oral papillae. Teeth, but no definite cluster 

 of tooth-papillae. 



Genital pores small, situated near together at the outer end of the 

 oral shield. Arm-bones have special forms approaching those of the 

 Astrophytons. Mouth-frames strongly ossified. 



The genera belonging to this family are Hemieuryale, Ophioplus, 

 and Sigsbeia. 



Hemieuryale pustulata Von Martens. 



Hemieuryale jmsfulata Von Mart., Monatsb. Konig. Akad.' Berl., p. 484, 1867; 



Ljung., Dr. Goes., Oph., Ofv. Kong. Akad., p. 617; Lyman, Ann. Sci. Nat., 



xvi. Art. 4, p. 5; Bull. Mus. Comp. ZooL, iii, 10, p. 268, pi. v, figs. 8-11; 



op. cit., X, p. 277; Eeport Voy. Challenger, Zool. Ophinroidea, v, p. 249, 



pi. xliii, fig. 7-10 (anatomy), 1882. 

 Ophiura cuspidifera (?) Lamk., Hist. Anim. s. Vert., iii, p. 226, 2d ed. , 1840 ; 



Encyclop. Meth., pi. cxxii, figs. 5-8. 



Disk small, thick, swollen, pentagonal, with a swelling opposite 

 the base of each arm when dried ; whole surface, except radial 

 shields, covered with larger and smaller thick scales and verrucae. 

 The central primary scale is round and rough like the radial shields, 

 but not swollen. Five primary rounded radial scales, which are 



