OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 85 

 OPHIALCOEA CONGESTA (Koehler). 



Plate 15, figs. 6, 7. 



Ophiacantha congesta Kcehler ('04), p. 103, pi. 24, figs. 1, 2. 

 Ophialcoea congesta H. L. Clark ('15), p. 217. 



Localities. — Albatross station 5219; between Marinduque and 

 Luzon; Mompog Island (NE.) bearing N. 35° 30' W., 22.70 kilo- 

 meters (12.25 miles) distant (lat. 13° 21' 00" N., long. 122° 18' 

 45" E.) ; 969 meters (530 fathoms) ; April 23, 1908; gn. M. 



Five specimens (Cat. Nos. 41265, 41267, 41268, U.S.N.M.). 



Albatross station 5527; between Siquijor and Bohol Islands; 

 Balicasag Island (C.) bearing N. 14° W., 15.20 kilometers (8.2 miles) 

 distant (lat. 9° 22' 30" N., long. 123° 42' 40" E.) 717 meters (392 

 fathoms) ; August 11, 1909 ; glob. Oz. 



Two specimens (Cat. No. 41266, U.S.N.M.). 



Notes. — Three of the specimens from from station 5219 are almost 

 of the same dimensions as the type of the species. The diameter of 

 the disk measures from 7 mm. to 9 mm., and the arms are between 

 40 mm. and 45 mm. long ; in another specimen from station 5527 the 

 diameter of the disk is 5.5 mm. The others are smaller and their 

 disks do not exceed 3 mm. or 4 mm. in diameter. 



Judging from the form of the upper arm plates and the form of 

 the arm spines, this species should be placed in Verrill's genus 

 Ophialcoea, where it falls near O. nuttingii Verrill, and O. tubercu- 

 losa (Lyman). It is, however, sharply distinguished from these two 

 species; O. nuttingii has the mouth shields large and oval, and 

 the dorsal surface of the disk is covered with small spines, which 

 leave the radial shields naked, while O. tuberculosa, in which the 

 mouth shields have a form similar to that which is found in O. con- 

 gesta, has the dorsal surface of the disk covered with large granules, 

 and the radial shields of each pair, which are very close together, are 

 separated by a deep and elongated depression ; furthermore, the arm 

 spines are more slender. 



The arm spines of O. congesta are thick and short; in the Albatross 

 specimens the dorsal spines of the first segments especially show a 

 remarkable thickness, but their width rapidly diminishes. 



Ophialcoea congesta was found by the Siboga at two stations be- 

 tween latitude l°-5° S. and longitude 119°-130° E., at depths of 450 

 and 798 meters (240 and 439 fathoms). 



OPHIENTREMA LEUCOSTICTUM (H. L. Clark). 



Plate 8, figs. 1-4 ; plate 10, rig. 5 ; plate 94, fig. 1. 



Ophiacantha leucosticta H. It. Clark ('11), p. 235. 

 Ophientrema leucostictum H. L. Clark ('15), p. 217. 



Locality. — Albatross station 5606; Gulf of Tomini, Celebes: 

 Dodepo Island (W.) bearing K 3° W., 20.01 kilometers (10.8 miles) 



