OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 413 



Albatross station 5670; Macassar Strait; Chenoki Point bearing S. 

 GO E., 74.13 kilometers (40 miles) distant (lat. 1 19' 00" S., long. 

 118 43' 00" E.) ; 2,160 meters (1,181 fathoms) ; December 30, 1909; 



gy- M - 



Some specimens (Cat. No. E. 175 [part], U.S.N.M.). 



Notes. A number of variations of this species, which is very 

 widely distributed at great depths, have been described by puthors. 

 The mouth shields and the plate which follows them on the central 

 surface of the disk in particular show rather variable outlines. I 

 include figures of the ventral surface of three specimens in order to 

 show the differences in the form of the mouth shields including the 

 majority of the ordinary cases; these three specimens came from sta- 

 tion 5349. In the specimen shown in figure 7 the shields are almost 

 as long as broad and trifoliate in form ; the plate which follows them 

 is short, and very much broader than long. In the specimen shown 

 in figure 8 the shields are triangular and elongated, very much longer 

 than broad, with the sides straight; the interradial plate which fol- 

 lows is still broader than long, but a little shorter than in the preced- 

 ing specimen. In the specimen shown in figure 9 the mouth shields, 

 which are trifoliate, are deeply notched by the bottom of the genital 

 slits, and they are longer than broad ; the following plate is almost as 

 broad as long, and sometimes even slightly longer than broad. 



In these different specimens, and in others such as those which 

 Liitken and Mortensen have figured ('99, pi. 3, fig. 10), the same 

 proportionate size of the mouth shields and of the plate which fol- 

 lows them in reference to the dimensions of the other ventral plates 

 of the disk is maintained. In a specimen from station 5652 the 

 size of the mouth shields, as well as that of the following plate, is 

 .extremely reduced, and it scarcely exceeds that of the other plates 

 of the ventral surface. 



The number of arm spines may exceed the figures usually given. 

 Liitken and Mortensen, who have recorded different variations in 

 O. lymani, give the number six to eight as being usual. More re- 

 cently MacClendon ('09, p. 36), in recording a specimen in which 

 the diameter of the disk is 30 mm., also gives six to eight spines. I 

 find in the majority of the large specimens that these spines are very 

 much more numerous, and 10 to 12 are not rare; on the arm which 

 1 show on plate 86 as figure 5, which is from a specimen from station 

 5349, some segments may even bear as many as 13 arm spines. 



OPHIOMUSIUM MO'RIO, new species. 



Plate 89, figs. 3, 4. 



Locality. Albatross station 5392; between Samar and Masbate; 

 Tubig Point bearing N. 49 E., 9.27 kilometers (5 miles) distant (lat. 



