MUSEUM OF COMPARATIVE ZOOLOGY. 225 



Ophiocoma brevipes Peters, insularia Lym., and ternispina v. Mart. 



I have examined great numbers of these, especially in the Museum Godef- 

 frov and the Museum of Comparative Zoology, and do confess myself much 

 puzzled. They ail agree in being completely and closely granulated, above 

 and below, and in having very regular, cleanly cut arm-plates. The variation 

 in color is from dark brown, through gray, and reticulated in patterns, to 

 pure white. It would seem that 0. brecipes (originals at Berlin) has five 

 spines on the first eight joints, and then four, and that the upper are the 

 longest. 0. insularia has four spines at the base of the arm, and the upper 

 are the shortest; the disk granulation is coarser, only six or seven in the 

 length of a mm. 0. ternispina has but three spines, which are tapering, 

 cylindrical, and often bent. A number of specimens, supposed to be 0. bre- 

 vipes, from the Philippines, had only four arm-spines at the base of the arm; 

 there were from nine to twelve grains in the length of a mm. On present 

 evidence it will not do to bring these three under one head. As to O. 

 squamala M. T. the original at Paris is lost, and nobody can now tell what 

 it was, though it might have been 0. brecipes. 



Ophiocoma alternans (von Martens, Oph. Ind. Oc, p. 251). I found, 

 by the Berlin original, that this is only the young of some species, probably 

 O. scolupendrina. 



Ophiarthrum pictum. 



Ophiocoma picta Mull, and Trosch., Syst. der Asteridcn. 

 Plate VII., Figs. 2-4. 



Special Marks. — Disk ornamented with meandrine brown lines ; a dark 

 line along the upper arm. Three ringed arm-spines, the upper one lomnx. 



Description of an Individual. — Diameter of disk 15 mm. Width of arm 

 ■without spines 3 mm. Distance from outer side of mouth-shield to inner 

 points of mouth-papillae to that between outer corners of mouth-slits, 3 : 4. 

 Mouth-papillae four (rarely three) on each side, the outer one tapering and 

 pointed; the next wider than long and rounded; the two innermost as broad 

 as long, and bead-like. Tooth-papillae (including as such all those under the 

 teeth) fifteen to seventeen, of nearly equal size, bead-like ; arranged in two 

 outer vertical rows of four or five each, with a more irregular central row, 

 and two or three odd papillae below. Teeth four, upper one largest and 

 broadest; all stout and thick, with rounded corners and a straight cutting 

 edge. Mouth-shields nearly round, faintly pointed within; length to breadth 

 2 : 2. Side mouth-shields thick, nearly joining their neighbor of the next 

 mouth-shield; within, running to a point, but not meeting. Under arm- 

 plates about as broad as long, clearly defined and regular, with outer side 

 slightly curved and lateral sides re-enteringly curved ; length to breadth 

 VOL. III. 15 



