File:Geological magazine (1890) (14577421710).jpg

Identifier: geologicalmagazi371890wood (find matches)
Title: Geological magazine
Year: 1864 (1860s)
Authors: Woodward, Henry, 1832-1921
Subjects: Geology
Publisher: London (etc.) Cambridge University Press
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
rst led me to suspect that the form and arrangementof the cranial plates differed in some material points from what isgiven in Mr. Whiteaves sketch.1 Close observation by means ofa good lens enables one, however, also to observe the original linesof suture, due care being taken not to be deceived by fractures.Though the direction of these sutures is often indicated by depressedlines or slight grooves free from the tubercular ornament, yet theactual suture is not incised, but slightly raised like a very finethread, this being due to the manner in which the original lines ofseparation between the bones have become entirely filled up byosseous matter. The results obtained by noting these lines in connection with the concentric arrangement of the rows of tubercles being in all essential respects the same in all the specimens (six) which I have examined, and being furthermore in complete accordance with the information 1 Op. cit. p. 93, woodcut. Geol. Mag. 1890 Dec. III. Vol. VII. PI. III.
Text Appearing After Image:
R.H Traquair, lei PHLYCTy^NIUS. Dr. R. R. Traquair—A New Genus of Coccosteidce. 57 derived from the lines radiating from the ossific centres in aspecimen with the surface rubbed off, there can be no doubt thatthe true form and arrangement of the constituent plates of theshield has been arrived at. The pattern in two shields has beenrepresented in outline in PI. III. Figs. 1 and 2, and if the readerwill compare these figures with that which I have already given ofthe cranial shield of Coccosteus,1 the fundamental agreement as wellas the essential difference between the two will at once be perceived. The median occipital plate (m.o.) is more or less five-sided,elongate, truncated behind, pointed in front, where it is wedged inbetween the hinder thirds of the two centrals. Its ossific centre isnear the posterior margin, and is marked by a prominent elevationof the surface. On each side of the median occipital is placed theexternal occipital (e.o.), which, although differently shaped fr

Note About Images