Prof. F. M'Coy on some new Devonian Fossils. 483 



thin, foliaceous expansions, and has been then described as Ich- 

 thyodorulites of the genera Onclais, Ctenacanthus and Dipla- 

 canthus. I have however repeatedly noticed its contact with, and 

 gradual passage on each side into, the flat, similarly striated 

 frond. 



Extremely abundant in a bed of blackish Devonian shale in 

 Lantic and Lantivit Bays on the south coast of Cornwall near 

 Polperro, and striking into f'owey Harbour, accompanied by 

 occasional specimens of the Bellei'O'phon bisulcatus, Rom. (the 

 Devonian shell confounded with the Silurian B. trilobatus by 

 those English geologists who have quoted that species from the 

 British Devonian strata). 



{Col. University of Cambridge.) 



Steganodidyum Carteri (M'Coy). 



Sp. Char. Flattened expansions, often less than one line thick ; 

 internal cellular structure rather finer than that of the S. Cor- 

 nubicum : surface covered with subequal, elongate oval promi- 

 nent tubercles, averaging twice as long as wide (half a line 

 long), arranged sometimes in quincunx, sometimes in irregular 

 lines, the rows from half a line to one line apart, but usually 

 three to four tubercles in a space of two lines ; flat spaces be- 

 tween the tubercles marked with a parallel striation, usually 

 oblique to the tubercles, crossmg those which are but slightly 

 elevated, but obsolete on the more prominent ones (about nine 

 sulci in a space of one line) ; both tubercles and oblique sulci 

 punctured by the openings of the minute cell-mouths, which 

 are about their diameter apart, and averaging eight to nine in 

 a space of one line. 



This species is very much rarer than the S. Cornubicum, from 

 which it is easily distinguished by its tuberculated surface. I 

 have great pleasure in dedicating it to my friend Mr. Carter. 



Rare in the dark Devonian schists of Lantivit Bay, Cornwall. 



{Col. University of Cambridge.) 



Uncites lavis (M'Coy). 



Sp. Char. Longitudinally ovate, oblique ; entering valve when 

 young ovate, with the front and lateral margins broadly 

 rounded, when old becoming very gibbous and subrhomboidal 

 from the convergence of the sides to a narrow rounded 

 front ; receiving valve obtusely subcarinate along the middle 

 when old by the nearly flat sloping of the sides, the front 

 margin not perceptibly elevated, and the lateral margins nearly 

 horizontal ; beak very large, sharply pointed, and widely ai-ched 

 inwards obliquely to one side, the under part of the beak 



31* 



