i 4 o SCIENCE PROGRESS 



gation which we have seen has already proved profitable, 

 opens up a most promising field. 



Additional species both of Lepidodendron, Sigillaria and 

 Bothrodendron will no doubt be the subjects of further inquiry 

 in this respect. The cone of Sigillaria remains still unknown 

 from British Rocks in the petrified state. 



The Pteridosperme^: 



In an article in the second number of the new series of 

 Science Progress (1906) I gave some account of recent work 

 on the Pteridosperms, under the title " The Origin of Gymno- 

 sperms " (6). It is thus unnecessary to recapitulate these 

 important discoveries here. During the last few years no further 

 memoirs have been published in Britain bearing directly on the 

 status of this group, nor on the attachment of the seeds. The 

 impressions of seed-like bodies borne on a Sphenopterid frond, 

 described by the present writer (8) under the name Carpolithes 

 Nathorsti, have been shown by Nathorst (40, p. 10), on subse- 

 quent and chemical examination, to be of a doubtful nature, and 

 more possibly of the nature of fern fructifications, or of the male 

 organs of a Pteridosperm. At any rate, they do not appear to 

 be seeds and must thus be dismissed from any discussion on 

 the question of the seed-bearing habit of the Pteridosperms. 



The announcement of the discovery of the seed and male 

 organs of Heterangium, the most fern-like of all the Pterido- 

 sperms, has just been made by Miss Benson (15); her paper, 

 now passing through the press, will be awaited with interest. 



Several new seeds and stems belonging to the Pteridosperms 

 have been described, notably the stem Sutcliffia insignis, eluci- 

 dated by Scott (49) in 1906. Scott finds that Sutcliffia is the 

 most primitive member of the Medullosese yet discovered, 

 its simple monostelic structure adding " probability to the 

 suggestion that the Medulloseae, as well as the Lyginodendreae, 

 may have sprung from a type anatomically similar, apart from 

 details, to Heterangium" 



An important paper from the pen of Oliver (43) on Physostoma 

 ■elegans, Williamson, a seed formerly known as Lagenostoma 

 physoides, Williamson, has just appeared. This stem is ribbed, 

 and possesses at the apex a whorl of ten tentacles, surrounding 

 the pollen chamber. Both the ribs and tentacles are adorned 



