. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Fossil Teeth o/Myliobatis. 43 figured by Bucldand in his ' Bridgewater Treatise,' was selected by Agassiz as the type of this species, and described as noteworthy for its superficial striation and the relatively considerable breadth of the median plates. The latter are shown to be six times as broad as long, and almost invariably exhibit a greater or less amount of antero-posterior curvature. The teeth of the first lateral series are somewhat longer than broad, though both the
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Fossil Teeth o/Myliobatis. 43 figured by Bucldand in his ' Bridgewater Treatise,' was selected by Agassiz as the type of this species, and described as noteworthy for its superficial striation and the relatively considerable breadth of the median plates. The latter are shown to be six times as broad as long, and almost invariably exhibit a greater or less amount of antero-posterior curvature. The teeth of the first lateral series are somewhat longer than broad, though both these and those of the second series are not so elongate as in M. Dixoni. The coronal contour is fliat in the adult, as shown in the accompanying woodcut (fig. 2), and almost so in the The following specimens of lower teeth seem to represent successive stages in the dentition of this specific type, and five (nos. I., 11., IV., VI., IX.) are shown in PI. I. figs. 5- 9. Nos. IX. to XI. are unusually large, and may be cer- tainly regarded as pertaining to overgrown individuals, although the last was described by Dixon as the type of a new species, M. irregularis. Lower Dentition o/"Alyliobatis striatus. No. of Specimen, Breadth of Length of Brit. Mus. Median Plate. Median Plate, I. P. a 0013 0-003 II. P. 1507 b 0023 0-0045 III. P. a 0031 0-006 IV. P. 3049 a 0038 0-007 V. P. 3043 0-042 0-0075 VI. 38838 0-054 0-009 VII. P. 3040 0059 0-0085 VIII. 25666 0065 0-009 IX. 40252 0-074 0-009 X. 25667 0-080 0 009 XI. P. 423 0100 0011 In the same series also we may evidently place the speci- men figured by Dixon as M. Edwardsii (B. M. no. 25615), which is intermediate in size between nos. III. and IV., and has similar relative proportions. This fossil is very much abraded, and thus not so satisfactory as coidd be wished -, but, like several others, it appears only to difi'er from the. Please note that these images are extracted from scanned page images that may ha
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