. The Cyathaspididae; a family of Silurian and Devonian jawless vertebrates. Cyathaspididae. DENISON: THE CYATHASPIDIDAE 385 lateral edges where they are somewhat finer. The rostral epitegum is covered with denticles and short ridges; antero-medially there are irregularly arranged denticles and short ridges; behind this is a band. Fig. 125. Vernonaspis sp., anterior part of dorsal shield, CNHM, PF 863 (X4). of short transverse ridges, then denticulations posteriorly. Some pores of the supraorbital canals are surrounded by circular ridges. This specimen shows many similarities to Vernonaspis ma
. The Cyathaspididae; a family of Silurian and Devonian jawless vertebrates. Cyathaspididae. DENISON: THE CYATHASPIDIDAE 385 lateral edges where they are somewhat finer. The rostral epitegum is covered with denticles and short ridges; antero-medially there are irregularly arranged denticles and short ridges; behind this is a band. Fig. 125. Vernonaspis sp., anterior part of dorsal shield, CNHM, PF 863 (X4). of short transverse ridges, then denticulations posteriorly. Some pores of the supraorbital canals are surrounded by circular ridges. This specimen shows many similarities to Vernonaspis major but is smaller and has weaker postbranchial lobes. Princeton 17043 is an incomplete dorsal shield in counterpart from the Late Silurian, High Falls formation, road cut on Dela- ware Water Gap-Millbrook road, opposite Shawnee Island, Warren County, New Jersey. The length of the dorsal shield is about 36 mm. and there are about 6 dentine ridges per millimeter. The epitega and ridge pattern are similar to other species of Vernonaspis. How- ever, this specimen is somewhat larger than other species from this region, and the median rostral process is small. Pionaspis1 new genus Type-species.—Pionaspis planicosta, new species Diagnosis.—This genus includes large-sized Cyathaspidinae with rather broad shields. The epitega are distinctly separated by ridge pattern and apparent sutures, but the postrostral field is not distin- guished from the central epitegum. The dorsal shield lacks a median rostral process, has deep orbital notches, and has short, deep post- branchial lobes with their anterior edges abruptly truncate. The 1 From iriov, plump; and aa-ins, 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 Denison, Robert H. (Robert Howland), 1911-1985; Chicago Natural History Museum. Chicago : Chicago
Size: 2043px × 1223px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorchicagonaturalhistorymuseum, bookcentury1900, bookcoll
