OPHIUROIDEA OF THE BAHAMA EXPEDITION. g 



Ophiozona impressa Lyman, 111. Cat. Mus. Comp. Zool., I, p. 64, fig. 4, 

 1865. Verrill, Notes on Radiata, Trans. Conn. Acad., I. p. 342, 1868. 

 Lyman, Report Voy. Challenger, Zool. Ophiuroidea, V, p. 21, pi. 

 XXXVII, figs. 13-15, 18-S2, anatomy; Bull. Mus. Comp. Zool., X, p. 

 235, 1883. 



Off Havana, no to 160 fathoms, 3 examples. It occurs 

 from Florida to St. Thomas, in shallow water. 



Ophiozona nivea Lyman. 



Ophiozona nivea Lyman, Illust. Catal. Mus. Comp. Zool., vol. VIII, 

 p. 9, figs. 85-86, 1875; Bull Mus. Comp. Zool., vol. V, p, 128,221; 

 Three Cruises of the Blake, II, p. 110, fig. 390, 1888. 



Variety, compta Verrill. 



Plate III; Figure 2, 3, 4. 



The original description of this species does not apply well 

 to a large number of specimens subsequently obtained, nor are 

 the outline figures correct. Therefore, I have given new 

 figures, part of them from specimens sent to me by Mr. Ly- 

 man, and have prepared the following more detailed descrip- 

 tion. The figures represent a variety with separated radial 

 shields, which I have named var. compta. 



Arms five, disk rather flat, rounded, covered with rather 

 large, unequal, irregular flat plates; five larger ones, in line 

 with the radial areas, surround a large central one, or 

 sometimes a group of two or three or more smaller central 

 ones; five large interradials, and five similar marginal inter- 

 radials are also conspicuous, forming five interradial rows. 

 Radial shields irregularly sub-triangular, with the broader 

 outer ends nearlv or quite in contact or separated by a row of 

 two or three small plates; the inner ends divergent, separated 

 by one large wedge-shaped plate and usually one or two 

 small ones; a triangular plate which lies between their outer 

 ends, is bordered on each side by a somewhat thickened, 

 rather crescent-shaped plate, around which there are several 

 small supplementary plates, and in the notch between them 

 lie the first three small and short, dorsal arm-plates. 



