MESOZOIC llADIATA. 51 



lamellje extending over it), the thin easily lost outer wall, and 

 the lamellse being very thick and simply meeting in the centre 

 without a cellulose axis. 



Montlivaultia gregaria (M'Coy). 



Sp. Char. Corallum forming turbinate masses (about 3 inches 

 wide and nearly 2 inches high) of few individuals which ter- 

 minate on the upper surface as prominentj disconnected, cir- 

 cular, slightly concave or convex discs with obtusely rounded 

 margins, generally \^ inch in diameter, with about eighty 

 thick radiating lamellae^ many of which reach the centre, the 

 rest being irregularly smaller ; connecting vesicular plates very 

 delicate ; external wall covering the lamellse very thin, rarely 

 preserved. 



The individuals of which the turbinate masses are composed 

 are identical in generic character with the ordinary Montlivaidtiaj 

 as the term is here used ; but no other species that I know has 

 this gregarious mode of growth, nor will any other genus con- 

 tain the species. 



Common in the inferior oolite of Dundry and Cheltenham. 



{Col, University of Cambridge.) 



IkndrophylUa plicata (M*^Coy) . 



^p. Char. Corallum of approximately straight stems from 1|^ to 

 2 lines in diameter, giving oiF at an angle of about 60° branch- 

 like cells averaging 3 lines long and slightly less in diameter 

 than the stem, arranged spirally at short irregular distances ; 

 surface with fine longitudinal punctured striae (about seven in 

 the space of one line) ; for rather more than a line from the 

 edge of each cell, every alternate superficial ridge becomes 

 narrowed and depressed, the intervening ones suddenly ac- 

 quiring a greater thickness and prominence, giving a plicated 

 appearance to the ends of the branches ; cellular axis and alter- 

 nating lamellse of the star as in the allied species of the 

 genus. 



This species most resembles the Lithodendron [Dendrophyllia) 

 granulosa (Miinst.) of the Abtenau tertiary beds, of which Gold- 

 fuss has given a tolerably good figure in his ' Petrefacten,^ but 

 the stem is smaller, not flexuous nor marked with annular con- 

 strictions ; it is also much more finely striated, and is remarkable 

 for the peculiar plication produced by the unequal projection of 

 the alternate ridges towards the mouths of the cells. 



Coralline oolite. Steeple Ashton. 



{Col. University of Cambridge.) 



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