16 Prof. H. A. Nicliolson on some new or 



Ohs. The only example which I possess of this remarkable 

 Stromatoporoid is a small polished fragment from the Devo- 

 nian Limestone of Devonshire, which I purchased from 

 Mr. Sclater, of Teignmouth. The structm-e of the skeleton 

 differs so widely from that of the ordinary species of Laheclua 

 that it is unnecessary to compare it minutely with these. 

 The characteristic features of L. serotina are the confluence of 

 the radial pillars into a reticulation of sinuous rows, the large 

 size of the axial canals, the presence of curved transverse par- 

 titions in the interior of the axial canals of the pillars, and the 

 fact that tlie interstitial tissue is composed of straight hori- 

 zontal plates, which only rarely become vesicular, and then 

 only to a very limited extent. 



I may mention that there exists in the Devonian limestones 

 of Devonshire another form of Lahechia^ the structure of 

 which accords essentially with that of the normal species of 

 the genus. I have not, however, as yet completely investi- 

 gated this form, and shall therefore defer its description to a 

 later time. 



Formation and Locality. Middle Devonian of Devonshire. 

 The specimen is in a red limestone, and is probably from the 

 neighbourhood of Torquay. 



Labechia ? Schmidtiiy Nicli. (PI. II. figs. 6-8.) 



Lahechia conferta, Fr. Schmidt, Silur. Form, von Ehstland &c. 



p. 2.30 (1858). 

 Labechia conferta, Liudstrom, Ami. & Mag. Nat. Hist. ser. 4, vol. xviii. 



p. 4 (1876). 

 Lahechia conferia (" Oesel'sche Form "), Dybowsld, Die Clisetetideii 



der cstbaltisclien Silur-Formation, p. 5-5, pi. iii. figs. 7, 7« (1877). 

 Lahechia confcrta, Ferd. Roemer, Leth^a Palfeozoica, p. 543, fig. 126 



(1883). 



Coenosteum in the form of laminar expansions, attached by 

 a basal peduncle, and having the rest of the lower surface 

 covered by a concentrically-striated epitheca. The coenosteum 

 may be of very considerable size, and its thickness varies from 

 a couple of millimetres up to perhaps two centimetres. The 

 upper surface is in many cases studded with very prominent 

 and large tubercles, which are placed close together in oblique 

 lines, but which rarely touch or become confluent. The free 

 extremities of the tubercles are in some specimens round, in 

 others pointed, and they mostly show no openings at their 

 apices. In some cases there is the appearance of apical 

 apertures ; but it seems probable that this is only the result 

 of wearing down of the surface. In many specimens the 

 whole or a large part of the surface may be covered with a 

 thin calcareous membrane, which passes over the summits of 



