PAL.^OZOIC CONE-GENUS LEPIDOSTEOBUS. 209 



particularly valuable, on account of the good preservation of the structures external to 

 the axis. 



When examining Wild's Cone, I was struck by a feature which has not been recorded 

 as occurring in this species— the presence, namely, of a delicate radial plate of sterile 

 tissue arising from the floor of the sporangium and appearing in tangential sections 

 merely as a streak * (Text-fig. 1). It resembles the outgrowth figured by Williamson t in 



Text-fisr.- 1. 



, - spm, 



Radial section of a sporangium and sporoph\ll of Lepkhstrohis oldhamhts. Will., " Wild's Cone," Williamson 



Collection, Brit. Mus. (Xat. Hist.) C.5. 1776 13. ( x 32 circa.) 



{l.p. = sporophyll pedicel ; l.t. =. sporophyll trace ; spm.iv. =r sporangium wall ; st.j). =: plate of sterile tissue 



arising from the floor of the sporangium.) 



the case of L. Veltheimianus^ except that it does not, as a rule, bifurcate, although it 

 may occasionally branch at the apex. It happens that, in the case of Williamson and 

 Binney's original cone, there are scarcely any good tangential sections passing through 

 a sporangium attached to its sporophyll ; so we cannot get a view of the sterile plate 

 comparable with that obtained in the preparation of Wild's Cone. In one of the 

 sections of the original cone in the Binney Collection $, however, two of the sporangia 

 are cut with great exactness in the radial plane, and in both these cases there arc 

 distinct indications of the presence of a plate of sterile tissue arising from the floor of 

 the sporangium and lying approximately in the plane of section. 



That tliis plate of sterile tissue within the sporangium is actually characteristic of the 

 type form of L. oldhamiua is confirmed by certain sections in Dr. Scott's Collection. 

 A sporophyll with a sporangium from one of these § is shown in PI. 27. fig. 55. 



• 



Wild's Cone are preserred in the Manchester rniversity Collection, and 



plates can also be observed ; e. g,, R. 384 5. 



t WiiUamson, W. C. ('73), p. 295 k pi. ' 

 t Binney Coll., No. 87. 



§ 



