LABECHIA STYLOPHORA. 161 



1 mm. apart, their size and height being variable (Plate XX, fig. 4). The only 

 known specimen is about 2\ cm. in length by 2 cm. in width. 



I have felt much hesitation in giving a name to this form, as I have only a 

 single small specimen of it, and have therefore been unable to examine its internal 

 structure by means of thin sections. It is clear, however, that we have to deal 

 here with a species of Labechia which is distinct from L. conferta. The young 

 form of the latter (Plate III, figs. 9 and 10) is an exceedingly thin, coin-shaped 

 plate, epithecate below and tuberculate above. On the other hand, the specimen 

 here described as L. scabiosa is not coin-shaped, and it is uncertain whether it is a 

 young example or is fully grown. Moreover, the character of the tuberculatum 

 of the upper surface is very distinct from that shown in young examples of L. 

 conferta, the tubercles being larger and more remote, while their distribution is 

 irregular and does not show any radial tendency, and they are commonly multiple 

 in structure. 



Distribution. — Wenlock Limestone, Dudley. 



3. Labechia stylophora, n. sp. PL XX, figs. 7 and 8. 



The coenosteum in this species is of unknown form, but is probably laminar. 

 It consists of irregularly undulated lamina3, traversed by strong radial pillars, and 

 so disposed as to give rise to the- formation of a number of cylinders, which run 

 at right angles to the general mass (Plate XX, fig. 7) . The cylinders are about 

 8 or 9 mm. in diameter, and are placed about 5 mm. apart ; and the radial pillars 

 within them are so arranged as to be parallel with the axis of the cylinders in the 

 middle line, while they are directed more or less transversely to the cylinder 

 towards the circumference of the latter (Plate XX, fig. 8). The radial pillars are 

 rounded or somewhat quadrangular in form, about two occupying the space of 

 1 mm. ; and the interstitial vesicular tissue is exceedingly delicate, four or five 

 vesicles occupying the space of a millimetre measured vertically. 



Owing to the peculiar state of preservation of all the specimens of L. stylophora 

 which I have seen, thin sections fail to yield any information further than that 

 afforded by polished slabs. The species is, however, clearly distinguished from 

 all other known forms of the genus by its unique mode of growth, its characteristic 

 cylinders reminding one closely of the similar structures seen in the coenosteum 

 of Actinostroma verrucosum, Goldf . sp. 



Distribution. — Not very uncommon in the Middle Devonian Limestones of 

 Shaldon, South Devon. 



