418 On a new Species of Nebalia y?'om New Zealand. smooth on its inner margin, or only slightly denticulated. Second gnathopoda very slender. Posterior pleopoda bearing a smooth sickle-shaped finger, with a few long cilia at its base. Terminal uropoda almost as long as antennae, five-jointed, and with numerous seta?. Length 0*18 inch. Ilab. Dredged along with the previous species in Dunedin Harbour, in 4-5 fathoms. EXPLANATION OF PLATE XIX. Figs. 1-6. Fig. 1. Arcturus tuhereulatus (male). X 13. Fig. 2. The same (female), head and part of body, x 13. Fig. 3. The same, superior antenme. X 56. Fig. 4. The same, lamellar plate of abdomen. X 28. Fig. 6. Tanais nova-zealandire. X 13. Fig. 6. The same, extremity of last pair of legs. X 28. XLVIT. — On a new Species o/'Nebalia from New Zealand. By George M. Thomson. [Plate XIX. figs. 7-9.] In dredging during the past summer in Dunedin Harbour I obtained a single specimen of a Nebalia differing from any species hitherto described, and which, from the great length of its inferior antenna?, I have named N. longicornis. In a paper in the Linnean Society's Transactions for 1875 (ser. ii. vol. i.), "On some Atlantic Crustacea of the ' Chal-lenger' Expedition," Dr. Willemoes-Suhm described a new species of Nebalia from Bermuda (N. longijoes), in which the phyllopodal character of the legs has been entirely lost, and the schizopodal character approached more than in any other species of the genus. Taking this fact in conjunction with the characters of several new deep-sea genera of Sehizo-pods examined by him, he reopened the whole question of the position which Nebalia occupies in reference to other groups of Crustacea, and proposed to unite it with these new forms, the Mysidse, &c, in the enlarged group of the Schizopoda. Seeing, however, that it differs from all others of the family in the number of its segments, in the well-developed phyllo-podal character of the thoracic appendages in the majority of the species, and also in its development, it seems a better plan to adopt the proposition made by Dr. A. S. Packard, Jun. (in the ' American Naturalist,' vol. xiii. p. 128), viz. to make it the type of a new order, the Phyllocarida. As he points out, Nebalia probably represents a persistent form of a very
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