. Breviora. 10 BREVIORA No. 503. Figure 4. Leptocephalus of Cyema atrum (after Smith, 1989b). 101025 (1, 16), 27°'N, 73°'W, 304 m, 16 Feb 1989. Pa- cific (1, 10 mm SL): USNM 324783 (1, 10), 29°47'36"N, 179°03'54"E, 50-100 m, 9 Feb 1985. IDENTIFICATION AND RELATIONSHIPS Leptocephalus holti and the larva o{ Cyema atrum (Fig. 4) share the following characters: a long, peg-like snout with a straight profile; a posteriorly placed eye; a gut with an anterior swelling at the hepatogastric region followed by two to four arches or loops; pigment dorsally on each gut loop; pigment near
. Breviora. 10 BREVIORA No. 503. Figure 4. Leptocephalus of Cyema atrum (after Smith, 1989b). 101025 (1, 16), 27°'N, 73°'W, 304 m, 16 Feb 1989. Pa- cific (1, 10 mm SL): USNM 324783 (1, 10), 29°47'36"N, 179°03'54"E, 50-100 m, 9 Feb 1985. IDENTIFICATION AND RELATIONSHIPS Leptocephalus holti and the larva o{ Cyema atrum (Fig. 4) share the following characters: a long, peg-like snout with a straight profile; a posteriorly placed eye; a gut with an anterior swelling at the hepatogastric region followed by two to four arches or loops; pigment dorsally on each gut loop; pigment near the dorsal margin of the body; an acute tail without distinct hypural elements; a large ventral blood vessel conspicuously separated from the gut tube; and V-shaped myomeres with a highly obtuse angle at the midlateral line. These characters distinguish Cyema atrum and L. holti from all other leptocephali and support the hypothesis that they belong to the same family. Cyema atrum (Fig. 4) has a deeper body than L. holti with a steeper anterior profile, it has an expanded mass of pancreatic tissue that fills much of the space between the dorsal margin of the intestine and the ventral margin of the myomeres, and its lateral pigment is scattered over the side of the body instead of being restricted to the midline. If L. holti is accepted as a cyematid, which cyematid is it? Both Castle (1977:75) and Smith (1989b:947) have made the obvious suggestion that L. holti is the larva of Neocyema, but they con-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harvard University. Museum of Comparative Zoology. Cambridge, Mass. , Museum of Comparative Zoology, Harvard University
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