OPHIURANS OF THE PHILIPPINE AND ADJACENT WATERS. 209 



broadens slightly toward the distal border of each upper arm plate 

 and narrows a little toward their middle ; the upper arm plates and 

 likewise the side arm plates, are also studded with very small blue 

 spots; the ventral surface is yellowish gray. The spines are trans- 

 parent and slightly bluish. I give here for comparison two photo- 

 graphs of one of the Siboga specimens upon which I based the species 

 and which will better serve to show the characters than my schematic 

 drawings of 1905 (figs. 3, 4). I also show on plate 97, as figure 2, 

 two of the first ventral arm spines transformed into hooks with three 

 branches of the type most usual in Ophiothrix (a), as well as two 

 tentacle scales (b) ; these last are small and delicate, and terminate 

 in a rather long point. 



The type of 0. armata came from Banda; it is a strictly littoral 

 form. 



OPHIOTHRIX ASPIDOTA Miiller and Troschel. 



Plate 32, figs. 1-5 ; plate 33, fig. 7 ; plate 97, fig. 3. 

 See for bibliography : 



Ophiothrix aspidota KOEHLEB ('04a), p. 87, figs. 50-54. H. L. CLARK ('15), 

 p. 269. 



Locality. Albatross station 5321; Ibugos Island (south end) 

 bearing S. 89 W., 2.32 kilometers (1.25 miles) distant (lat, 20 19' 

 30" N., long. 121 51' 15" E.) ; 47 meters (26 fathoms) ; November 

 9, 1908; wh. S., Co., brk. Sh. 



One specimen (Cat. ]\o. E. 9, U.S.N.M.). 



Notes. The diameter of the disk is 9 mm. The arms are not pre- 

 served for a greater length than 40 mm., but judging from the frag- 

 ments which accompany the specimen, and which appear to me to 

 represent a total length of more than 80 or 90 mm., they must be very 

 long; the arms are flattened and remain of the same width over a 

 very large part of their length (figs. 3, 4, 5). 



The club spines of the dorsal surface of the disk are short, rather 

 broad, and ordinarily terminate in three subequal spinules; some- 

 times these spinules are four in number, or two only ; it may happen 

 that one of them is greatly elongated at the expense of the others 

 (pi. 97, fig. 3a). Toward the borders of the disk the club spines be- 

 come a little longer and more slender. The first ventral arm spine 

 becomes transformed rather rapidly into a hook which never becomes 

 very large, and which may show as many as eight or nine subequal 

 points on its concave side; the convex side also often shows some 

 asperities toward the terminal part (pi. 97, fig. 3&). The following 

 spines bear very closely crowded and much elongated teeth on their 

 proximal border, while the teeth are short, conical and few on the 

 distal border (fig. 3c and d). The tentacle scale is elongated and 

 ends in a sharp point (e). 



55269 22 Bui. 100 14 



