PALEOZOIC COllALS AND FORAMINIFERA. 79 



of closely superposed conical plates, connected by a few fine 

 vertical lamellae : lamelliferous zone surrounding the axis nar- 

 row, of about forty-two alternately broad and rudimentary 

 lamellse, the interstitial plates of which are nearly horizontal : 

 outer zone wide, formed of large arched plates, not highly in- 

 clined, and forming a loosely vesicular structure : terminal star, 

 axis very prominent, oval, vertically ribbed, but not twisted, 

 seated in a deep oval or circular cup, lined by the strong ra- 

 diating lamellae ; outer zone nearly flat, oblique at the sides, 

 faintly marked with rather distant, fine lines, representing the 

 strong radiating lamellae of the inner zone, continued to the 

 boundaries of the cells, which are strong, prominent and 

 slightly crenulated. 



A vertical section shows first, the outer largely vesicular area 

 formed of broad, curved, slightly inclined plates ; between this 

 and the inner area there is a fine vertical defining line, within 

 which the plates of the inner zone are seen to be finer and closer 

 than those of the outer, forming a smaller cellular structure ; the 

 rows of cells are nearly horizontal near the outer zone, but within 

 seem gradually to bend up and become continuous with the co- 

 nical cup- like plates forming the axis ; those conical plates of the 

 axis s6em connected by extremely delicate, irregular, radiating 

 plates j in a rough transverse section the axis appears as a deep 

 conical hollow on the und^'r side. It will thus be seen that in the 

 remarkable cone-in-cone structure of the axis this resembles the 

 Russian Stromhodes mammillare and S. astroides [Lithostrotion id. 

 of Lonsdale), from both of which it difi*ers in the axis not being 

 twisted in the terminal star, in the outer zone not being traversed 

 by strong radiating lamellae, from the former in the much less 

 obliquity of the plates of the outer area, and from the latter by 

 the largely cellular structure of the outer area, as well as the di- 

 stinctness of all the three areas under every circumstance. In 

 general appearance and imperfect radiation of the outer area it 

 resembles the S, emar datum and S.floriforme {Lithostrotion id. of 

 Lonsdale), but is distinguished from the first by the rudimentary 

 radiating lamellae between the primary ones, and from both by 

 the conical structure of the axis, which is formed in them of 

 irregularly twisted vertical plates. 



Not uncommon in the carboniferous limestone near Bakewell, 

 Derbyshire. 



(Col. University of Cambridge.) 



Lonsdaleia (M^Coy), n. g. 



Gen. Char. Corallum composed of circular, tapering, proliferous 

 stems, rarely, if ever, laterally united ; internally composed of 



