20 September 1993 PROC. BIOL. SOC. WASH. 106(3), 1993, pp. 545-553 TWO NEW RECORDS OF THE GENUS HEPTACARPUS (CRUSTACEA: DECAPODA: HIPPOLYTIDAE) FROM JAPANESE WATERS Tomoyuki Komai Abstract. — Two species of the hippolytid genus Heptacarpus, H. maxillipes (Rathbun, 1902) and H. moseri (Rathbun, 1902), both of which have been known mainly from the eastern Pacific Ocean including the Bering Sea, are recorded from Japan for the first time on the basis of specimens collected from the Pacific coast of northern Japan. The identification was confirmed by com- parison with American specimens. For each species, a synonymy and detailed description, including the color pattern of fresh material, are given. The hippolytid genus Heptacarpus Holmes now contains 33 species, which are all restricted to the North Pacific Ocean. Hayashi (1992) reported 11 species from Japan and its adjacent waters, all from lit- toral or sublittoral zones. Recent collections from the Pacific coast of northern Japan revealed the presence of two bathyal species of Heptacarpus, H. maxillipes (Rathbun, 1902) and H. moseri (Rathbun, 1902). These two species have been reported from the eastern Pacific in- cluding the Bering Sea (Rathbun 1902, 1904; Butler 1980), and H. maxillipes has been reported near Kurile Islands (Birshtein & Zarenkov 1970). Since descriptions of these two species by the previous authors are in- adequate, I describe them herein in detail. The following abbreviations are used in the text: CL, postorbital carapace length; HUMZ, Laboratory of Marine Zoology, Faculty of Fisheries, Hokkaido University; USNM, National Museum of Natural His- tory, Smithsonian Institution, Washington, D.C. Heptacarpus maxillipes (Rathbun, 1902) Figs. 1A, 2, 3 Spirontocaris maxillipes Rathbun, 1902: 898.-Rathbun, 1904:92, fig. 40. Heptacarpus maxillipes. — Holthuis, 1947: 12 (list).-Birshtein & Zarenkov, 1970: 420.-Hayashi, 1979:12, tab. 1.-Hay- ashi, 1992:110, tab. 32. Material examined. — HUMZ-C 936, East of Cape Erimo, 42°02.3'N, 144°07.9'E, 915- 970 m, 6 Sep 1989, otter trawl (T/S Oshoro- Maru), 1 female (5.5 mm CL), coll. T. Ko- mai; HUMZ-C 1003, offFukushima Pref., 37°07.5'N, 142°41.2'E, 412 m, 1 Jun 1989, otter trawl (R/V Tanshu-Maru), 2 females (6.8 mm CL), coll. O. Yamamura. Comparative material— USNM 183004, Aleutian Islands, 2 males (5.1, 5.2 mm CL), 1 female (7.0 mm CL). Description. —Integument thin, smooth. Rostrum (Fig. 2A) slightly curved upward, reaching or slightly overreaching distal end of antennular peduncle, 0.86-0.89 times as long as carapace, with ventral blade rather deep and dorsal blade poorly developed; lat- eral carina axis-like, sharply ridged proxi- mally; apex sharply pointed; dorsal margin with 6 teeth over entire length, including 2 on carapace posterior to orbital margin, posteriormost tooth situated at anterior l A of carapace; ventral margin convex, with 4 small teeth on distal %. Carapace (Figs. 1 A, 2A, B) with suborbital lobe rounded from dorsal aspect, falling far short of antennal