NOKTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 25 



This species is so near P. cylindrica (Hutton) that it is not without 

 much hesitation I have kept them separate. On comparing speci- 

 mens of the two species with each other there are, however, certain 

 differences which seem to be constant and which give the two species 

 quite unlike facies. The color of cylindrica, although variable, is 

 chiefly shades of gray and brown, with no tendency to pink or purplish- 

 red, the dominant shades in anchista. The arm spines of cylindrica 

 are also less flattened and are truncate, particularly the lowest, rather 

 than pointed. The arms themselves, moreover, are as a rule more 

 flattened in cylindrica than in anchista and more arm spines are visible 

 when looking down on the animal from above. Finally, cylindrica is 

 a smaller species, 7 to 9 mm. across the disk, with shorter arms, only 

 three or four times diameter of disk. Since cylindrica has not yet 

 been taken outside of the New Zealand region, it seems best to me to 

 regard these trivial differences as specific, at least for the present. 



OPHIARACHNELLA GORGONIA. 



Ophiarachna gorgonia MULLER and TROSCHEL, Sys. Ast., 1842, p. 105. 

 Ophiarachnella gorgonia CLARK, Bull. Mus. Comp. Zool., vol. 52, 1909, p. 123. 



Locality. Japan, one specimen. 



As I have elsewhere a discussed in some detail the relationships of 

 this genus and the synonymy of this species, I do not need to go over 

 the ground here. Suffice it to say that this specimen from Japan is 

 a fine example of Pectinura stearnsiilves, agreeing in all particulars 

 with the figures and description of that species, which was based on 

 a single large specimen from Japan. Ives' type was 30 mm. across the 

 disk, while the one before me is even larger, measuring a full 33 mm. 

 The examination of this specimen has confirmed my opinion that 

 stearnsii can not be distinguished from marmorata Lyman, of which 

 it is doubtless the fully grown adult. Nor can I find, from the mate- 

 rial I have examined, or from the descriptions and figures which have 

 been published, any satisfactory characters by which marmorata is to 

 be distinguished from gorgonia. 



OPHIARACHNELLA MEGALASPIS, new species.& 



Disk 12 mm. in diameter; arms 50 to 55 mm. long. Disk pentag- 

 onal, covered with a close, fine granulation (100 to 175 granules to the 

 square millimeter); radial shields and one or more (usually three) 

 small rounded plates distal to them, just at the base of the arm, bare. 

 Radial shields very large (about 2.5 mm. long by 1.5 mm. wide), 

 smooth and bare; distance between the two shields of a pair is less 

 than the width of a shield and much less than the mterradial dis- 



aBull. Mus. Comp. Zool., vol. 52, 1909, pp. 121-123. 



bMtfae (pe-faX-), signifying big, and daxle, signifying shield, in reference to the large 

 radial shields. 



