A. E. Verrill — North Ainerican Ophiuroidea. 303 



Class OPHIUROIDEA. 



Order I. OPHIUR^ Miiller & Troschel, 1842. 



Ophiurce Ljungman, Oph. Viv., p. 308, 1867. Verrill, 1899a, p. 4. 

 Ophiuridoi Lyman, and many other authors. 

 Zygophiurce and Streptophim'os. Bell, 1893. 



Family, PECTINURIDiE Verrill, 1899. 



Ophiodermatido} Ljung., Oph. Viv., p. 87, 1867. Lntk., Addit. Hist. Oph., 



iii, p: 87, 1869. 

 PectinuridK Verrill, Nat. Hist. Biill. Univ. of Iowa, v, p. 4, 1899a. 



The generic name, Ophioderma, is now recognized only as a 

 synonym of Ophiura. Therefore I have changed the name of this 

 family, as is customary in such cases. The name Ophmridm cannot 

 properly be used for the family group here included, because Mr. 

 Lyman and many others have always used it to designate the order 

 Ophiurw, or all the Ophiuroidea exclusive of the Euryaloe. 



Family, OPHIOLEPID^ Ljung., 1866. 

 Ophiozona nivea Lyman. 



Ophiozona nivea Lyman, Ilkist. Catal. Miis. Comp. Zool., vol. viii, p. 8, figs. 



85-86, 1875; Bull. Mus. Comp. Zool., vol. v, p. 128, 221 ; Three Cruises of 



the Blake, ii, p. 110, fig. 390, 1888. 

 Ophiozona nivea, var. coinpta Verrill, Nat. Hist. Bull., v, p. 9, pi. iii, fig. 



2, 1899. 



Variety, coinpta Verrill. 



Plate XLIII. Figures 1, la. 



The varietal name was given to the variety with distinctly sepa- 

 rated radial shields, regardless of the variations in the oral shields, 

 which happen to be, in both the specimens figured (pi. xliii, figs. 1 

 and la) of the shorter and more ovate form. 



A study of a series of specimens sent to me by Mr. Lyman (from 

 sta. 291, 200 fath., Blake Exp.) shows considerable variation in the 

 form of the oral shields. These are sometimes oblong, twice as long 

 as broad, with the outer and inner portions of the same width; in 

 other cases the outer pai't, beyond the lateral indentations caused 

 by the end of the genital slit, is broader than the inner part ; in 

 other specimens the outer part is narrower than the inner. The 



