22 BRITISH PERMIAN BRACHIOPODA. 



recurved again, and thus producing the first of the seven or eight convolutions of which 

 each cone is composed. From the first two spiral lamellae spring up perpendicularly other 

 two secondary ones (0, d), which, by being bent, become united towards the middle of the 

 shell (d) between the two spiral cones, and afterwards form but a single branch (from 

 d to e). This last, after having attained the upper level of the spire (at e), becomes again 

 bifurcated, and forms other two lamella? (/) recurved in half circle, and terminating back- 

 wards by a free extremity {g) between the first and second coil of each spiral cone. 



Obs. The discovery of the perfect example from which the above description has been 

 taken is entirely due to the zeal of Mr. Howse, who, along with Mr. Kirkby, had kindly 

 (and at my especial request) worked for several days in the quarry of Humbleton hill, in 

 the hopes of obtaining a specimen wherein the connecting process of the two spirals could 

 be satisfactorily viewed. It was not, therefore, until the 17th of September, 1856, that 

 material sufficiently perfect could be found so as to admit of a clear definition of this 

 singularly complicated system of lamella?, so difficult to describe, but which will be readily 

 understood by a glance at our several illustrations. 1 



In 1840 Mr. J. de C. Sowerby figured (in tab. 616 of the 'Mineral Conchology') an 

 imperfect specimen (54 of our PI. I), in which the perpendicular lamella? (t) are seen to 

 spring up from the first two spiral coils, as we have already described, and another 

 (PL I, fig. 53) in which a small unexplained portion of the connecting process was 

 exhibited (l). In this last example the attachment of the short bent lamella? to the 

 prolongations of the hinge-plate are likewise imperfectly displayed. 



Mr. J. de C. Sowerby and Professor King have referred to the pectinated character of 

 the spiral process, and to this I have likewise devoted some attention. The appearance is 

 considered by Mr. Howse to be more deceptive than real, and entirely due to a foreign 

 substance which encrusts the internal portions of the larger number of specimens. 

 Although this is to a certain extent correct, and that some spirals have not presented a 

 trace of pectinations, others were so distinctly marked, that after a careful examination I 

 felt disposed to believe that the appearance was in a measure due to short spines 

 (PI. II, fig. 5), similar to those first described by myself as existing on and near the edge 

 of the coils of Spiriferina rostrata, S. Miinsteri, Ter. resupinata, and other species, as 

 will be seen by a reference to Part I of the present work. 



The fringes which so closely encircle both valves are likewise of much interest ; and it 

 will be perceived (PI. I, fig. 55) that the spinose extremities become at times flattened and 

 expanded, so as to produce small plates of a limited extent. 



M. De Verneuil and Professor King have alluded to the resemblance which appears to 

 exist between the Carboniferous Athyris Boissyi and the Permian A. pedinifera ; but, 

 besides the more developed sinus peculiar to the Carboniferous shell, there would seem to 



l A small example had also been observed in the collection of the British Museum by Mr. S. P. 

 Woodward, but not nearly as perfect as the one discovered by Mr. Howse (PL II, fig. 2). 



