OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 295 



because of the absence of plates, and the thinness of the integument 

 which covers the underlying tissues. 



Affinities and distinctive features. Ophiogymna funesta shows a 

 very great resemblance to O. fulgens (Kcehler), and the dorsal sur- 

 face of the disk shows in the two species some almost identical char- 

 acters, both because of the existence of an integument covering the 

 underlying plates more or less encroaching upon the radial shields, 

 as well as on account of the armature, which may include small club 

 spines only, or may be a mixture of club spines and true spines, these 

 latter sometimes assuming a very great development. In both species 

 the upper arm plates may similarly break up, but their shape is 

 entirely different ; in O. fulgens they are as long as broad, or scarcely 

 broader than long, and they have the form of a dihedral angle with an 

 always very apparent median keel ; their lateral angles are rounded, 

 and the distal border is very convex. In O. funesta they are very 

 broad, flattened, and never carinate, and their distal border is straight 

 or even slightly excavated; the lateral angles are very sharp. I 

 have never found the least indication of intermediates between these 

 two forms. The arm spines are also a little longer and stronger in 

 O. funesta, and their tip is not swollen. 



But the two species are evidently very closely allied, and they may 

 be easily confused. I do not for a moment believe, however, that 

 they can be united, for it does not seem to me possible to deny the 

 importance of the differences which we have shown in the form of 

 the upper arm plates. 



OPHIOGYMNA PtTLCHELLA (Kehler). 



Plate 37, figs. 1, 5, 6 ; plate 43, fig. 11 ; plate 103, fig. 5. 



Ophtothrix pulchella KCEHLER ('06), p. 106, pi. 11, figs. 11, 12; pi. 15, fig. 

 3. H. L. CLARK ('15), p. 281. 



Localities. Albatross station 5131; Sulu (Jolo) Sea, off western 

 Mindanao ; island off Panabutan Point bearing N. 20 E., 0.74 kilo- 

 meters (0.4 miles) distant; 49 meters (27 fathoms); February 6, 

 1908; gn. M., co. S. 



One specimen (Cat. No. 41294, U.S.N.M.). 



Albatross station 5132; Sulu Sea, off western Mindanao; island off 

 Panabutan Point bearing N. 15 W., 0.55 kilometer (0.3 mile) dis- 

 tant; 47 meters (26 fathoms) ; February 6, 1908; gn. M., S. 



Two specimens (Cat. Nos. 41293, 41295, U.S.N.M.). 



Albatross station 5133 ; Sulu Sea, off western Mindanao ; island off 

 Panabutan Point bearing N. 52 E., 2.78 kilometers (1.5 miles) dis- 

 tant; 69 meters (38 fathoms) ; February 6, 1908; gn. M., S. 



One specimen (Cat. No. 41296. U.S.N.M.). 



