OCR Text |
Show 1888.] PROF. BELL ON NEW SPECIES OF OPHIURIDS. 283 distinctive characteristics-minute though some of them may appear to be-seem to justify the formation of a new species for this form. The description is drawn up from a single dried specimen. Disk distinctly, but not sharply, pentagonal; arms about four and a half times its diameter ; they are not carinated at their base, nor, on the other hand, markedly flattened; they taper gradually. Granulation of disk rather coarse, about nine granules to a millimetre; the radial shields not marked by special depressions. Mouth-shields not divided, irregularly lenticular, the more convex edge being adoral; side mouth-shields quite small; the granulation between the mouth-shield and the edge of the jaw is very coarse. Mouth-papillae seven, the penultimate quite twice the size of its neighbours. The upper arm-plates have pretty straight edges, and are about twice and a half as long as broad; the under arm-plates are not quite so much encroached upon by the side-plates as in O. conjun-gens, and are rather more regularly hexagonal; an aboral notch frequently found in the allied species is not to be seen in the one now under description. The side arm-plates carry ten subequal spines1, none of which are as long as the plate that bears them ; there are two tentacular scales near the base of the arm and one further out; there are two pores between the first and second arm-plates. It would be unsafe to form a judgment as to the colour of this species either when alive or as preserved in alcohol; but it is probably paler than 0. conjungens, and not so much mottled ; there are signs of sets of three joints at a distance of from seven to ten joints from one another being darker than the rest; this would give a banded appearance to the arms; the mouth-shields are probably darker than the rest of the oral surface. Diam. of disk 100 (ca.) m m ; length of arms 24 m m. Hab. Port Jackson ; in coll. B.M. 4. OPHIOGLYPHA AMPHITRITES, sp. nov. (Plate XVI. fig. 6.) This species appears to belong to Mr. Lyman's first division of the genus, or those in which the disk is flat and is "covered with imbricated scales. Under arm-plates small, widely separated ; much wider than long beyond the second plate, and thereafter constantly diminishing in size. Arm-comb of more or less needle-like papilla.. Arm slightly flattened, with spines about as long as a joint. Tentacle- scales few, beyond the second pair of pores." But it does not appear to be referable to any form yet described. Arms three to four times the diameter of the disk. Mouth-papillae five at the outer mouth-angle, separated by a bare space from the five (two on each side, and one larger central one) which lie just below the teeth, and have almost the appearance of teeth-papillse. Mouth-shield longer than broad, a little constricted in the middle, distal edge rounded, proximal forming an acute angle ; side mouth-shields long and narrow, meeting within. First under arm-plate broader distally than proximally, the second 1 0. conjungens may bear nine or ten arm-spines near the base of |