176 Dr. C. J. Forsyth Major. [June 15, 



sporangium is small there are neither trabeculee nor septa, the 

 exigencies of nutrition, and perhaps also of mechanical strengthening, 

 not being felt (Lycopodium) : where the sporangium is large sterile 

 bands of tissue are present ; these appear as trabeculse or incomplete 

 septa in Lepidodendron or Isoetes, but as complete septa in the large 

 synangia of Tmesipteris. To those who accept the homology of the 

 synangium of Tmesipteris with the sporangium of other Lycopodineae 

 the probability of this will appear specially strong. Such facts as 

 these and their theoretical bearing are discussed at length in the 

 memoir : the opinion is finally expressed that progressive sterilisa- 

 tion and formation of septa are factors which will have to be taken 

 into account in solving the problems of origin of vascular plants, and 

 especially of their numerous sporangia : such formation of septa will 

 have to be considered as one factor which may help to explain the 

 origin of the simpler vascular plants from forms of some Bryophytic 

 character, in which the sporogenous tissue was one continuous band. 



In the course of the investigation it has become apparent that it 

 is not possible to give any strict topographical definition of the arche- 

 sporium which shall apply for all Vascular Cryptogams. This will not 

 surprise those who have recognised that the position of the arche- 

 sporium is not fixed for all Bryophyta, while, on the other hand, the 

 first segmentations which lead to the definition of the archesporium 

 in Vascular Cryptogams do not correspond to those in Phanerogams, 

 where there is a definite dermatogen. 



The memoir, of which this is a brief abstract of a few 'of the 

 salient points, is still incomplete : it is intended shortly to treat the 

 spore-bearing members of the Filicinese from a similar point of view, 

 and in preparation for this a considerable number of observations 

 have already been made. In the meanwhile, it may be stated that 

 the main lines of argument pursued above in treating the strobiloid' 

 forms will be found to be applicable also for the Filicineas. The 

 second part will also include a general discussion of the whole subject. 



XVI. " On Megaladapis madagascariensis, an Extinct Gigantic 

 Lemur oid from Madagascar." By C. J. FORSYTE MAJOR, 

 M.D., For. Cor. Zool. Soc. Lond., &c. Communicated by 

 Dr. H. WOODWARD, F.R.S., V.P.G.S., &c. Keceived June 

 14, 1893. 



(Abstract.) 



The subject of the present paper is a somewhat imperfect Mam- 

 malian skull, together with a right and left mandibular ramus, 

 apparently belonging to the same specimen, discovered by Mr. J. T. 

 Last (collector for the Hon. Lionel Walter de Rothschild), in a 



