OPHIUBANS OF THE PHILIPPINE AND ADJACENT WATERS. 229 



On plate 97, as figure 4, 1 give some photographs of the trifid club 

 spines of the dorsal surface of the disk (a), of the hook which the 

 first under arm spine very rapidly forms and which has three or 

 four branches (5), of the second and third arm spines (c), and of 

 the small tentacle scale which has a very long point (d) . 



OpMothrix exigua appears to be very widespread throughout the 

 whole Indo-Pacific region; it is known to occur in the Red Sea, in 

 the Philippines, in the Mergui Archipelago, and at numerous sta- 

 tions in the Sunda Islands, where the Siboga found it between and 

 36 meters (0 to 20 fathoms). It is always littoral. 



OPHIOTHRIX EXPEDITA Kcehler. 



Plate 31, fig. 6 ; plate 33, fig. 5 ; plate 98, fig. 5. 



OpMothrix expedita Kcehleb ('05), p. 96, pi. 9, figs. 10-14; pi. 15, fig. 5; 

 ('10), p. 294.— H. L. Claek ('15), p. 272. 



Localities. — Albatross station 5147; Sulu (Jolo) Archipelago, in 

 the vicinity of Siasi; Sulade Island (E.) bearing N. 3° E., 15.57 kilo- 

 meters (8.4 miles) distant (lat. 5° 41' 40" N., long. 120° 47' 10" E.) ; 

 38 meters (21 fathoms) ; February 16, 1908; co. S., Sh. 



One specimen (Cat. No. 41390, U.S.N.M.). 



Albatross station 5149; Sulu Archipelago, in the vicinity of Siasi; 

 Sirun Island (W.) bearing N. 39° E., 4.45 kilometers (2.4 miles) dis- 

 tant (lat. 5° 33' 00" N., long. 120° 42' 10" E.) ; 18 meters (10 fath- 

 oms) ; February 18, 1908; Co., Sh. 



One specimen (Cat. No. 41388, U.S.N.M.). 



Albatross station 5165; Sulu Archipelago; Tawi Tawi Group; Ob- 

 servation Island bearing N. 70° W., 11.86 kilometers (6.4 miles) dis- 

 tant (lat. 4° 58' 20" N., long. 119° 50' 30" E.) ; 16 meters (9 fath- 

 oms) ; February 24, 1908 ; Co. 



One specimen (Cat. No. 41389, U.S.N.M.). 



Notes. — The three specimens agree perfectly in morphological char- 

 acters, as well as in coloration, with the type which I described from 

 the specimens collected by the Siboga at different stations in the 

 Sunda Archipelago. In the specimen from station 5149, which is 

 the largest, the diameter of the disk reaches 19 mm. ; the two others 

 are smaller. 



The photographs which I give here will complete the notes which 

 I have already given on O. expedita. It will be noticed that the hook 

 formed by the first ventral arm spine (pi. 98, fig. 5d) by the rather 

 numerous points along its concave border strongly recalls the form 

 which I have described in O. aspidota and in O. coronata, and which 

 we find again in O. longipeda and in O. puncto-limbata. 



The dorsal surface of the disk bears club spines mixed with true 

 spines, which are sometimes very long and which are more or less 



