On the ' Challenger ' Cejfhalopoda. 181 on the chitinous coat and the surface of the other free at the circumference ; cemented together and held in position by the microcell-structure or " float," which, projecting above the level of the outer heads of the birotules, gives rise to the roughened state of the surface of the statoblast. Chitinous coat and germinal contents the same as in the Spongillge generally. Size of specimen sent to me about ^ x^ inch horizontally. Hab. Fresh water. Log. " Ice-Factory Lakes, De Land, Florida, near the St. John's River." Obs. The extremely delicate character of the spiculation generally, the microspined skeletal spicules, the great length of the birotules, and the radiating portions of the head being horizontal and not recurved at their extremities, allies this species more to Meyenia Jluviatilis than to the Heteromeyenice (e. gr., Spongilla Baileyiy Bk., Proc. Zool. Soc. 1863, pi. xxxviii. fig. 6) of Mr. Potts. Hence the name. XX. — Diagnoses of new Species of Cephalopoda collected during the Cruise of H.M. 8. ' Challenger.'— Fsivt II. The Decapoda. By William E. Hoyle, M.A. (Oxon), M.R.C.S., F.R. S.E.J Naturalist to the ' Challenger ' Commission. [Published by permission of the Lords Commissioners of H.M. Treasury, and extracted from a paper read before the Eoyal Society of Edinburgh, July 6, 1885.] MyopsidaB. Promachoteuthis, Hoyle. Promachoteuihis, Hoyle, 1885, Narr. Chall. Exp. vol. i. p. 273, fig. 109, The Body is short, rounded, with large broad fins, situated posteriorly. The mantle is free behind, as in Rossia. The siphon is short and slender and with everted margin ; valve ? The Head is small and narrow ; eyes not prominent. The Arms are long and conical, with two series of pedun-culate spherical suckers. The tentacles exactly resemble the arms at their origin ; the club is absent. The Gladius has not been removed from the single example.