Mr. F. J. Bell on two new Species o/"Asteroidea. 333 EXPLANATION OF THE ILLUSTRATIONS. Plate XIV. Fit/. 18. Contents of the Altmiihl-valley diluvium, a, spiniferous spi-cule, characteristic average largest size ; b, the same, smallest size ; c, vermicular spicule ; h, birotulate spicule ; all drawn to the same scale, viz. l-48th to 1-UOOOth inch, to show their sizes relatively, d, group or aggregated mass of vermicular spicules ; e, various forms of the vermicular spicule ; scale l-24th to 1-GOOOth inch. /, vermicular spicule, more magnified, to show trace of a central canal, y, the smaller size of spiniferous spi-cule ("&"), more magnified, to show the form aud recurvature of the spines in the smaller spicules generally; i, tbe birotulate " A," more magnified, to show the form of the shaft and arms; k, pollen-grain of Conifer ; /, tetraspore of acot3dedonous plant. The two latter on the scale of l-24th to 1-G000th inch. XXXVIII. — Descriptions of two new Species of Asteroidea in the Collection of the British Museum. By F. Jeffrey Bell, M.A. The Asterias now to be described was not satisfactorily re-cognized as an undescribed form at the time when I gave to the Zoological Society some account of the genus to which it belongs *. The Culcita has been long known to me as a new form, but I have refrained from publishing any account of it, in the hope that it might soon be possible to make a revision of the group to which it belongs. As it is now, however, ex-hibited in the new galleries of the Zoological Department at South Kensington, the student will probably find it con-venient to have an account of it. Asterias nautarum. General formula, 2 aa' . Arms five, do not begin to taper till the last third of their length, broadest at a short distance from their base ; two rows of adambulacral spines ; madreporic plate anechino-placid, obscure, not far from the margin of the disk. Spines autacanthid, very blunt on abactinal surface. The abactinal surface presents an appearance of very close packing, as there are on it three rows of autacanthid spines ; those of the outer-most are very fairly developed. This last-mentioned row bounds the lower, while a row as well marked bounds the * P. Z.S. 1881, p. 492. Ann. & Mag. N. Hist, Ser. 5. Vol. xii. 24
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