Devonian.-] PALiEONTOLOGY OF VICTORIA. [Animals. 



rows of pores on the corresponding faces of the tube than with 

 true radiatino- lamellpe. 



Abundant in the Middle Devonian limestone of Buchan. 



Explanation of Figures. 



Pliite XXXV. — Fii;;. 1, portion of mass, natural size, showing exterior of prismatic columns 

 as exposerl in rough fracture. Fig. la, portion of ditto, magnified, sliowing tlie tumid edged 

 communicating pores varying from one to two or three vertical rows on each face. Fig. lb, 

 portion of upper surface, natural size. Fig. le, vertical section, magnified, showing the variable 

 distance of the transverse diaphragms or tabula. Fig. \d, upper surface, magnified, of one of 

 the transverse diaphragms or tabular, showing the one, two, or three indentations Uke incipient 

 radiating lamellae on each straight side. 



Plate XXXV., Figs. C-?5. 

 SPIRIFERA L^VICOSTA (Val.). 



[Genus SPIRIFERA (Sow.). (Sub.-kingd. Mollusca. Class Palliobranchiata. Ord. Brachio- 

 poda. Fani. Spiriferidie,") 



Gejt. Char. — Transversely oval, gibbous, radiatingly-ridged ; hinge-line as long as the shell 

 is wide ; area nearly parallel-sided, of moderate width in the receiving valve, very narrow in 

 the opposite one ; shell fibrous, foramen notching the area of both valves, that of the entering 

 valve open, that of the receiving valve with an internal pseudo-deltidium liordered by two strong 

 diverging dental lamella; in the receiving valve ; and by the flattened bases of the spiral 

 npophyses in the other, which .also usually shows a small mesi.al septum ; casts of receiving 

 valve are trilobed towards the beak, the sm.all middle lobe being defined by the ends of the 

 diverging dent.al lamella; on each side, its rounded end (analogous to a pseudo-deltidium) as 

 well as those of the lateral lobes being formed by an inner layer of shell, between which and 

 the external one is a wide hollow space. The muscular impressions of the great valve .are 

 shallow, radiated jnst within the ends of the dental lamina; ; those of the entering valve (in the 

 Permian S. alatiis and the Silurian 6'. Li/ni) resemble those of Orthis, tlie four impressions 

 being rounded and grouped together on the rostral half of the middle, their bouudaries forming 

 a more or less distinct crucial nmrk, depressed in casts.] 



Description. — Rotundatn-quadifito, very g-ibhous, slig-litly wider tlmn lonfc ; 

 hinp-e-line slifilitly sborter thnn the widtli of the sliell, obtusely rounding' the lateral 

 cardinal angles; caidinal area concave, moderately wide ; beaks small, moderately 

 incurved; large valve with a wide deep concave mesial furrow distinctly defined to 

 the beak, and 12 or 13 simple obtusely rounded or subangular ribs on each side; 

 the mesial fold of the smaller valve is smaller than the sintis, only moderately convex, 

 often with a slight mesial sulcus. Surftice nearly smooth, with a few lines of growth 

 near the edge, and under a strong lens slightly gmntilo-punctate perhaps by the 

 ends of the fibres of the shell tissue. Usual width, 1 inch i lines; projjortional 

 length of large valve, ^W J "^ smallei' valve, -j^ji ; depth of both valves, -{^^^ ; width 

 of cardinal area, 3 lines; width of mesial hollow at front, (i lines. 



Reference. — = Tereh atula hrv'tcoxtata, Valenciennes in Lam. Hist. Nat. des 

 Anim. sans Vertebres, v. 4, p. 1, "!j9. ^ IcrchraHditcs ont'wlatus, Schlotheim 

 Kachtrag'. zur Petiefactenkundc, t. 17, f. 3. 



[ K^ ] 



