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Show 1879.] THE COREAN AND JAPANESE SEAS. 57 This species has apparently a very wide geographical range, as there are specimens which do not seem to differ specifically in the British Museum from the Gulf of Suez and Western Australia ; and I am informed in a letter from Mr. J. S. Kingsley, of the Peabody Academy of Science, Massachusetts, that the Museum of that Institution possesses specimens from Hong-Kong, the Sandwich Islands, and Zanzibar. CUM ACE A. HETEROCUMA, gen. nov. Cephalothorax without a distinct rostrum, and (viewed laterally) nearly straight in its dorsal outline. Five free segments of the body exposed. Postabdomen much longer than the carapace, terminal segment obsolete. Eye large and distinct. Antennules robust, 5- jointed, without any accessory flagellum, and with the first three joints of the peduncle dilated. Mandibles with the apex strongly dentated, the inner margins armed with 10-12 stiff setae and with a prominent molar tubercle. First maxillae with the slender flagella terminating in two unequal setae. First and second maxillipeds 6- jointed; third maxillipeds 6-jointed, the basal joint considerably dilated, and produced at its extero-distal angle, which is subacute, the second joint very short, transverse, the third with its extero-distal angle greatly produced and acuminated, the fourth dilated and truncated at its distal extremity, and the fifth and sixth slender. First three pairs of legs palpigerous in both sexes. The appendages of the sixth postabdominal segment (uropoda) are elongated, the basal portion being about as long as the fifth postabdominal segment, and terminating in two flattened subequal rami, which are two-jointed and about as long as the base. In the males there exist well-developed appendages on the ventral surface of the first five postabdominal segments, and the antennae are well developed and have the last joint of the peduncle dilated and terminate in a slender flagellum, which is directed backward and is as long as the animal. This genus is apparently nearly allied to Eudorella, Norman (Eu-dora, S. Bate), which it resembles in general form, the obsolescence of the terminal postabdominal segment, the form of the uropoda, &c, but differs in the existence of a well-developed eye, in the structure of the flagellum of the first maxilla, which terminates in two setae, and particularly in the dilatation of the third and fourth joints of the third pair of maxillipeds. In the males, moreover, the first five postabdominal segments are all furnished with appendages. It is also very nearly allied to Leptocuma, Sars, from Rio Plata, a genus recently described and beautifully figured by its distinguished author in Kongl. Vetensk.-Akad. Handl. xi. no. 5, p. 24 ; but in that genus the eye is indistinct, and not furnished with corneae, the first pair of legs more robust, and, moreover, the third maxillipeds (so far as they could be seen without dissection in the unique specimen) are described as "of perfectly normal structure" in Leptocuma. |