1876.] 



Fossil Plants of the Coal-measures. 



71 



M. Brongniart as pollen-grains — an opinion in which the author concurs. 

 External to the lagenostome the second or outer division of the nucular 

 membrane forms a remarkable " canopy," which hangs down from the 

 micropyle, enclosing the lagenostome within ten sharply defined and 

 regular crescentic folds, the concavities of which are directed outwards. 

 The walls of this lagenostome and of the " canopy " correspond with the 

 nucular membrane in consisting of flattened prosenchymatous cells. The 

 perispermic membrane, on the other hand, looks structureless, save that it 

 appears to have had imbedded in it an innumerable multitude of 

 minute crystals, like those observed by Dr. Hooker on the spicular cells 

 of Welwitschia. ^ 



A second species the author designates Lagenostoma pJiysoides. In this 

 the apex of the endospermic sac contracts into a mammilliform prolonga- 

 tion, overlapped by the base of the lagenostome, which overhangs it as a 

 bladder half -full of water might be made to overhang the neck of a soda- 

 water bottle upon which it rested. This species has other distinctive 

 structural peculiarities. 



Eor a second genus of new seeds the author proposes the name of 

 Conostoma. oblonga from Oldham is about 'IS of an inch in length. 

 Here, again, we have an endosperai enclosed in a perispermic membrane, 

 and this in turn is encased within a nucular one, the whole being invested 

 by a dense testa. The lagenostome is again formed out of divisions of 

 the apical part of the nucular membrane ; but it assumes a funnel-shape 

 at its base, whilst its upper extremity is continuous with the micropyle. 

 A second species, named'C. ovalis, is from the Burntisland deposit, and is 

 more ovate than C. oblonga. In it the lagenostome assumes a remarkably 

 funnel-shaped contour. The same deposit has furnished a third species, 

 ^C. intermedia. To another remarkable seed from Oldham the author 

 gives the name of llalacotesta ohlonga, of which the maximum length, 

 exclusive of its funiculus, has been about -25. Its exotesta has been 

 soft and parenchymatous, mth a prosenchymatous inner (nucular?) 

 membrane. The micropyle has been remarkably wide with incurved 

 margins at the exostome, aad enclosing a mass of delicate parenchyma 

 through which a canal passed. 



The author ha? obtained a fine series both of longitudinal and trans- 

 verse sections of Trigonocar^um olivceforme, the seed long ago made the 

 subject of a valuable memoir by Dr. Hooker and Mr. Binney. So far 

 as the longitudinal sections are concerned, the results obtained correspond 

 closely with those already arrived at by these two authors, except that 

 a modified form of lagenostome is shown to have existed at the apex of the 

 nucleus. The transverse sections show that the two layers of the testa, 

 an outer soft parenchymatous exotesta and an inner sclerotesta, present 

 some striking features. The exterior of the latter has exhibited three 

 principal, acute, prominent, longitudinal ridges, between each two of 

 which are three intermediate ones, the centre of these three being 



