. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. FLOWER AND WAYLAND-SMITH: CYATHASPID FISHES 377 bear essentially linear ridges. In front of this, and seemingly attached to the rostrum, is a similar small plate the surface of which shows the ridges developed into whorls, suggestive of the lateral plate figured by Kiaer and Heintz (1935, PI. 33, fig. 1,) for Homalaspidella niiida, but with finer ornamentation. The pustules of the ridges on the middle part of the plate are tiny, but well elevated. The markings on the posterior part are somewhat irregular, but essentia
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. FLOWER AND WAYLAND-SMITH: CYATHASPID FISHES 377 bear essentially linear ridges. In front of this, and seemingly attached to the rostrum, is a similar small plate the surface of which shows the ridges developed into whorls, suggestive of the lateral plate figured by Kiaer and Heintz (1935, PI. 33, fig. 1,) for Homalaspidella niiida, but with finer ornamentation. The pustules of the ridges on the middle part of the plate are tiny, but well elevated. The markings on the posterior part are somewhat irregular, but essentially linear. A ventral plate tentatively assigned to the same species, on the basis of form, is represented by an internal impression (PI. 2, figs. 6-7) and an impression of the exterior from which a rubber mold was taken (PI. 5, fig. 2.) The internal impression, 26 mm. long, 16 mm. wide, is quite strongly convex and, in flattening, the margin on the right has been bent under the remainder of the specimen. The anterior end which is imperfect, appears to be strongly truncate in front, and scarcely emarginate if at all. The posterior outline is obtusely angled in the middle, the oblique sides straight and meeting the lateral margins at a prominent angle. Lateral margins curved, greatest width attained shortly behind the middle of the plate. The impression of the interior is relatively smooth but (PI. 2, fig. 7,) shows a series of very faint ridges, which, however, it has proved impossible to distinguish with certainty from the cracks which are the result of slight crushing of the plate in flattening. In part, at least, these represent a portion of the lateral line system as in Arehegonaspis sp., but no clear pattern can be made out (Fig. 1).. Fig. 1. Ventral shield attributed to Vernonaspis leonardi, showing ob- servable pattern of fine ridges, and cracks of the surface, which cannot be properly differentiated. Part of this doubtless represents the lateral line system, which is he
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Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
