. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. BIGELOW AND SCHROKDER : NEW BATOID FISHES 239 One tail spine, the distance of its origin from center of cloaca about equal to distance from snout to first pair of gill openings, its length a little greater than distance from snout to mouth; very narrow, with a sharp point. Snout in front of orbits times as long as orbit, its length in front of mouth times as great as distance be- tween exposed nostrils, its tip slightly produced in a sharp point (see Fig. 22 for variations). Distance between orbits 5
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. BIGELOW AND SCHROKDER : NEW BATOID FISHES 239 One tail spine, the distance of its origin from center of cloaca about equal to distance from snout to first pair of gill openings, its length a little greater than distance from snout to mouth; very narrow, with a sharp point. Snout in front of orbits times as long as orbit, its length in front of mouth times as great as distance be- tween exposed nostrils, its tip slightly produced in a sharp point (see Fig. 22 for variations). Distance between orbits times as great as length of orbit. Orbit times as long as spiracle which is immediately aside and behind and notably larger. Nasal curtain fringed; outer fold of opening of nostril deep-set, with somewhat rough edge. Jaws slightly bowed, the lower with a shallow median indentation, the upper curved to correspond to the lower. Teeth with oval base, arranged more or less in quincunx, those of male in -|i- series, with a canine- like cusp directed inward, those of female in -||- series, with a low triangular cusp. The teeth of a very young male, only 117 mm long, already have rather prominent cusps, triangular in shape. The cusps on a female of 170 mm are barely discernible while one mature female of 232 mm has teeth with a very low, broad Figure 23. TJrotrygon micropthalmum, nostrils, nasal curtain and mouth of a male 222 mm long, about ; lower right, teeth from upper jaw about xl4; lower left, teeth from upper jaw of fe- male 234 mm long, about xl4. Drawing by N. W. 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. : The Museum
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