ox THE STKUCTUKE AND CLASSIFICATION 
2(0 
EXPLANATION OF PLATES VIII AND IX. 
Illu. 4 trating Dr. Henry Fairfield Osborn’s Memoir upon The Structure and Classificatiox 
OK THE Mrisozmc Mammalia; — 
The figures were drawn by the author with the aid of a camera,’ in.suring their accuracy of 
proi>ortion and outline. They are enlarged in some cases to seven diameters, and often reversed, 
to bring out clearly the comparative structural details. The enlargement is not proportional to 
actual size. Figures 1, 3, 5, S, 9, 10, 11, 13, 14, 15 are from single specimens ; the remaining 
seven are comf>osites} Composition figures are adopted in cases where two specimens of one indi- 
vidual fall in reversed slabs; or where two sj^ecimens, from different individuals, agree in size 
and contain two or more similar teeth in common. For example, in Bolodon, figure 16, parts of 
two maxilla- were thus united, both of which showed the maxillary suture and four similar teeth 
behind it. In most cases, the numbers attached to the original specimens in the British Museum 
collection are r(!Corded, in order to enable other investigators to confirm or disprove the compo- 
sition. In preparing the drawings, some parts were naturally more fully known and certainly 
r«-lnt*tl to each other than others. These degrees of probability are expressed in the draw- 
ings in the following manner: (1) In cases w-here there is positively no reasonable doubt as to 
the relation of two composite specimens (as in the Bolodon maxilla) the parts of each are fully 
shndeil, ns if they belonged U) one individual. (2) Where the outline of the teeth or jaw is 
ascertained from impressions left in the matrix, or where a specimen has fallen into two slabs 
one showing the inner, the other the outer surface, plain contour lines arc used. (3) Where the 
evidence is not from one of the comi>osites, but from another specimen belonging to the same 
g«-nus or sjH-cies, or where the presence of a tooth is somewhat conjectural, dotted lines are em- 
ploy, •<!. Thi-se ml, -8 an- all illustrated in the figure of Spalacotherium and are adhered to in all 
tlie ,lrawing» unless it is otherwi.se distinctly stated. 
Abhrex'uUwns. a, angle, r, condyle, d, dental foramen. /, infraorbital foramen. ///, mylo- 
hyoid groom, mf, mental foramen, r, mandibular symphysis, ms, maxiUo-premaxillary 
suture. /, (, p, m, dcntid series. 
I HE BRITISH MESOZOIC MAMMALS. 
-landibukr ramus, enlarged 4 
, T. ' frofesBor Owen', memoir, «Geo4ic.I 
1 ransaclions, &er. 2, Vol. VT Ploic irr >> -n • >6 
•nolars, m, was omitted. " ’ ^ 
““"dibulnr ramus, enlarged 
Plate II.” ■ ’ “nt'gewaler Treatises, Geology and Mineralogy, 
•lout, t.o„,e„l„rge«^meler,. The main portion of the mandible and 
».n, for “Z";" 1:,";:;;:::;^^ ■„ i...iu.bi. iae,n,. 
k the re«,u of the “mbZZTMwtlZmZrtlch r’”’*' ‘ Tie former 
