OPHIUEANS OF THE PHILIPPINE AND ADJACENT WATERS. 301 



much broader than long, and they are finally three times as broad as 

 long. These plates are not in contact, but remain separated from 

 each other by a narrow interval occupied by soft tissue. 



The side arm plates, which are rather projecting, bear at the base 

 of the arms four rather thick arm spines which are broadened at the 

 base with the tip rounded ; the two ventral spines are rather short ; 

 the two others are longer and their length may equal two segments 

 on the ten or fifteen first arm segments. The third spine is usually 

 a little longer than the fourth. Beyond the fifteenth segment the 

 spines become shorter, and they scarcely exceed the segment in length. 

 Seen under the microscope, the surface of these spines appears cov- 

 ered with fine asperities. 



The tentacle scale is small, short, and rounded, and its surface is 

 also provided with fine asperities. 



The color of the specimen in alcohol is black, with no ornamentation. 



Affinities and distinctive features. — The genus Ophiomaza up to 

 now has included only three species — O. cacaotica Lyman, O. moerens 

 Kcehler, and O. obscura (Ljungman). The new species, which most 

 certainly belongs to the same genus, differs from the three others, and 

 especially from O. cacaotica, by its very much smaller radial shields; 

 it is further distinguished from them by its large mouth shields 

 which with the genital plates cover a large part of the ventral surface 

 of the disk. 



Very recently Matsumoto has described a species from Japan — O. 

 kanekoi ('17, p. 227) — from which O. fusca also differs in the reduced 

 size of its radial shields and in the greater dimensions of its mouth 

 shields. H. L. Clark has referred to the genus Ophiomaza Brock's 

 Liitkenia cataphracta ('15, p. 283), which raises to six the total num- 

 ber of the species in the genus Ophiomaza. 



OPHIOPTERON ELEGANS Ludwig. 



Plate 60, figs. 1, 2, 5 ; plate 103, fig. 4. 



See for bibliography : 

 Oi)hioptcron elegans Kcehler ('04). p. 112. — H. L. Clark ('15), p. 282. 



Localities. — Albatross station 5136; in the vicinity of Jolo; Jolo 

 Light bearing S. 37° E., 1.30 kilometers (0.7 mile) distant (lat, 6° 

 04/ 20" N., long. 120° 59' 20" E.) ; 40 meters (22 fathoms) ; Feb- 

 ruary 14, 1908 ; S., Sh. 



One specimen (Cat. No. 41308, U.S.N.M.). 



Albatross station 5150; Sulu (Jolo) Archipelago, in the vicinity 

 of Siasi; Sirun Island (W.) bearing N. 34° E., 21.68 (11.7 miles) 

 distant (lat. 5° 23' 20" N., long. 120° 35' 45" E.) ; 38 meters (21 

 fathoms) ; February 18, 1908 ; co. S., Sh. 



Two specimens (Cat. Nos. 41310, 41311, U.S.N.M.). 



