Mr. T. Atthey on Anthracosaurus Russelli. 167 



EXPLANATION OF THE PLATES. 

 Plate VIII. 



Fiff. 1. Upper surface of cranium of Anthracosaurvs Russelli, one third the 

 natural size ; P.max, prsemaxilla ; M.g, mucus-groove ; A.n.o, 

 anterior nasal orifice ; N, nasal bone ; Max, maxilla ; L, 

 lacrymal bone ; Jii, jugal ; Qu.ju, quadrate-j ugal ; Qu, quadrate ; 

 S.t, supratemporal ; O. V, orbital vacuities ; F?; froutals ; P/'.fr, 

 prefrontal; Pt-fr, postfrontal ; Pt.O, postorbital; P, parietals, 

 with parietal foramen; (S'y, squamous ; <S. O?, supraoccipital, so 

 called; F, epiotic ; 7'.i^, temporal fossa ; 6'.0, supraoccipital; 

 F.S, exoccipital; Mand, anterior end of left mandible overlying 

 part of skull ; P.B. palate-bone, posterior end of right side dis 

 placed. 



Fig. 2. Upper, and fig. 3 under surface of a dermal scute : a, anterior 

 end. 



Plate IX. 



Under surface of same cranium, one third the natural size. P.max, prse- 

 maxilla ; F, vomer ; N. C, nasal channel ; Max, maxilla ; Pal, 

 palate-bone ; P. T, palate-tusk ; P.f.p, palate-teeth, small pos- 

 terior series ; O. V, orbital vacuities ; Pter, pterygoid bone ; 

 B.sph, basisphenoid ; Pr.sph, presphenoid ; Pr.fr, prefrontal ; 

 Z, lacrymal; Ju, jugal; Qu.ju, quadrate-j ugal; P.oc, basi- 

 occipital ; Qti, quadrate ; Mand, right ramus of mandible over- 

 lying part of right side of skull. 



Plate X. 



Fig, 1. Inner surface of right mandible of same, one third the natural 

 size. Ar, articular piece ; D, dentary ; S, splenial ; An, angular ; 

 Sym, symphysis. 



Fig. 2. Outer surface of left mandible, one third the natural size. Ar, 

 articular piece ; D, dentary ; An, angular ; Mg, mucus-groove. 



Fig. 3. Dorsal rib, two thirds the natural size. 



Fig. 4. Dorsal vertebra, natural size, entire. 



Plate XI. Sections of teeth of Anthracosaurus. 



Fig. 1. Transverse section of maxillary tooth near to apex and above pulp- 

 cavity, magnified 12 diam. E, enamel ; D, dentine. 



Fig. 2. Transverse section just below top of pulp-cavity. E, thin enamel ; 

 D.l, light dentine ; D.d, dark dentine ; P, pulp-cavity ; short 

 infoldings of peripheral bands {PI) into apices of fusiform light 

 dentine are seen, also rudimentary radiations of pulp-cavity. 



Fig. 3. Transverse section a little below fig. 2 and above the radiations of 

 the pulp-cavity, the rudiments of which are indicated as in 

 fig. 2. D.l, light dentine ; D.d, dark dentine ; P, pulp-cavity, 

 the infolded peripheral bands (PI) extend inwards two thirds of 

 the distance towards the pulp-cavity. 



Fig. 4. Transverse section a little below the level of the alveolar border. 

 D.l, light dentine ; D.d, dark dentine ; P, pulp-cavity ; PI, 

 peripheral band infolded ; P, irregular radiations of pulp-cavity. 



Fig. 5. Portion of fig. 4, magnified 48 diameters ',111, toothlets ; D.l, light 

 dentine ; Dd, dark dentine ; PI, peripheral band infolded and. 

 sinuous; PPP, pulp-cavity. 



12* 



