OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 205 



Lutken and Mortensen stated that they were not absolutely cer- 

 tain of their determination, but it seems to me beyond doubt that the 

 specimens which they described and figured belong to A. duplicata. 



Amphiactis duplicata must therefore have an enormous geographi- 

 cal range. 



The specimen from station 5658 has an appearance somewhat 

 different from that of the others (figs. 1, 2). It is a little larger and 

 the diameter of the disk reaches 7 mm. ; the dorsal surface is remark- 

 able for the thickness of the plates which cover it. These are very 

 stout, and the borders are much swollen, while the central region is 

 a little depressed; the arm spines are short and thick. But other- 

 wise the characters conform absolutely to those of A. duplicata, and 

 in this specimen we have to do merely with an exaggeration of the 

 thickness of the plates of the dorsal surface of the disk. 



Family OPHIOTRICHIDAE. 



OPHIOTHRIX ARISTULATA Lyman. 



See for bibliography : 

 Ophiothri.r aristtUata Kcehler ('04), p. 151. — Doderlein ('10), p. 254, pi. 5, 

 figs. -A, 5.— H. L. Clark ('15), p. 269; ('16). p. 89. 



Localities. — Albatross station 5517; northern Mindanao and vicin- 

 ity; Point Tagolo Light bearing S. 83° W., 19.46 kilometers (10.5 

 miles) distant (lat. 8° 45' 30" N., long. 123° 33' 45" E.) ; 309 meters 

 (169 fathoms) ; August 9, 1909; Glob. 



One specimen (Cat. No. E. 96, U.S.N.M.). 



Albatross station 5519; northern Mindanao and vicinity; Point 

 Tagolo Light bearing S. 71° W., 16.12 kilometers (8.7 miles) distant 

 (lat, 8° 47' 00" N., long. 123° 31' 15" E.) ; 333 meters (182 fathoms) ; 

 August 9, 1909 ; Glob., S. 



One specimen (Cat. No. E. 97, 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. 



Two specimens (Cat. Nos. E. 98, E. 99, U.S.N.M.). 



Notes. — The specimens which I previously described and figured, 

 which were dredged by the Investigator in the Indian Ocean (Anda- 

 man Islands and coast of Coromandel), have, as I wrote in 1896 

 ('96, p. 363), a more robust habitus and the radial shields are more 

 developed than in Lyman's type; the spines of the dorsal surface 

 of the disk are stronger and longer, and the arm spines are larger. 

 I felt myself justified in establishing on the basis of these differences 

 a variety which I called investigatoris, which, however, evidently is 

 of no great value, and the study of more numerous specimens from 

 different localities will no doubt show intermediates between this 

 variety and the type. 



