OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 337 



rachna Lyman attributes to this latter, as well as to the genus 

 Ophiocoma, very numerous tooth papillae arranged in a vertical 

 clump, which is quite contrary to the original diagnosis of Miiller 

 and Troschel. It is interesting to compare the diagnoses of the 

 genus Ophiocoma and of the genus Ophiarachna which were given 

 by Lyman in the Challenger reports ('82, p. 167 and 173) ; the 

 question arises b}' what character does Lyman distinguish externally 

 these two genera (I am not speaking of the differences in the form 

 of the peristomial plates). As Lyman's error has been repeated by 

 certain authors, and especially in Bronn's Thierreich (Echinodermen, 

 III, Schlangesternen, p. 939), it can not be noticed too often in order 

 that naturalists may be put on their guard against it. 



PBCTINURA AEQUALIS (Lyman). 



Plate 77, figs. 16, 17. 



Ophiopeza aequalis Lyman ('82). p. 12, pi. 27, figs. 7-9. — Kcehleb ('04), p. 10. 

 Pectinura aequalis H. L. Clakk ('09), p. 118; ('15), p. 303. 



Localities. — Albatross station 5415; between Cebu and Bohol; 

 Lauis Point Light bearing N. 24° W., 13.34 kilometers (7.2 miles dis- 

 tant (lat. 10° 07' 50" N., long. 123° 57' 00" E.) ; 161 meters (88 

 fathoms) ; March 24, 1909; fne. S. 



Two specimens (Cat. No. E. 279, U.S.N.M.). 



Albatross station 5523; northern Mindanao and vicinity; Point 

 Tagolo Light bearing S. 48° W., 12.42 kilometers (6.7 miles) distant 

 (lat. 8° 48' 44" N., long. 123° 27' 35" E.) ; August 10, 1909. 



One specimen (Cat. No. E. 280, U.S.N.M.). 



Albatross station 5541; Tagolo Light bearing S. 65° W., 23.54 

 kilometers (12.7 miles) distant (lat. 8° 49' 38" N., long. 123° 34' 30" 

 E.) ; 401 meters (219 fathoms) ; August 20, 1909, fne. S., brk. Sh. 



Three specimens (Cat. Nos. E. 281, E. 282, U.S.N.M.). 



Notes. — The diameter of the disk varies between 25 mm. and 30 

 mm. The specimens from stations 5415 and 5541 are almost com- 

 pletely decolorized; that from station 5523, which is the largest of 

 all, still has the dorsal surface of the disk pink, and the arms show 

 annulations which are alternately very light pink and a darker red, 

 these latter broader than the former. It is only in this specimen that 

 I find ten arm spines as indicated by Lyman ; usually the arm spines 

 are eight in number. 



The mouth shields 'are almost as long as broad. The two speci- 

 mens from station 5415 show a slight variation in their form ; in one 

 of them the mouth shields are slightly longer than broad and in 

 the other they are a little broader than long. I give photographs 

 of ventral surface of these two specimens (pi. 77, figs. 16, 17). 



55269— 22— Bull. 100 22 



