The Canadian journal of industry, science and art . Fig. 142. 30 A POPULAR EXPOSITION OF THE. Fig. 143. questioned whether all the separated caudal-shields referred to thattype, really belong to it.* The species are restricted, as far as presentobservation goes, to the lowest fossiliferous zone. Illcenus :—In this well-characterized genus, the shell-covering ismore or less smooth and comparatively free from furrows. Head,thorax, and pygidium are in most specimens nearly equal in broad, but feebly raised or otherwise defined. Eyes farapart. Body-rings generally ten(rarely eight or
The Canadian journal of industry, science and art . Fig. 142. 30 A POPULAR EXPOSITION OF THE. Fig. 143. questioned whether all the separated caudal-shields referred to thattype, really belong to it.* The species are restricted, as far as presentobservation goes, to the lowest fossiliferous zone. Illcenus :—In this well-characterized genus, the shell-covering ismore or less smooth and comparatively free from furrows. Head,thorax, and pygidium are in most specimens nearly equal in broad, but feebly raised or otherwise defined. Eyes farapart. Body-rings generally ten(rarely eight or nine) in almost or quite smooth,with even, rounded outline. Thegenus belongs to both the Lowerand Middle Silurian deposits, butis chiefly found in the middle andhigher parts of the lower 143 represents one of ourmost common species, from theTrenton and Hudson River is usually referred to IllcBnus crassicauda. A rolled-up ex-ample is shewn at a. JPhacops:—Glabella largely developed, expanded anteriorly, andoften granulated but not lobed. Facial-su
Size: 1711px × 1460px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, bookpublishertoron, bookyear1856
