fl()i;a of Till-: kootamk foumaiion. 287 



linear in shape and are cnt down nearly to the niidi-il) into strap-shaped 

 lacinia' that bear sori at their ends, where they ai'e slijj;htly broader than 

 in their other portions. Tlie width of these pinna> near their base is 

 about ',] mm., and they narrow sli<ilitly tow.ai'd tlicii- tips. None of them 

 were seen entii-e, but they were ai)pai'ently a little over 2 cm. in len<ith. 

 Both the midnerve and the lateral nerves seem to h.-ive Ihhmi sleiidei' and 

 conld not be distinc-tly seen. The sori at the ends of the lacinia« are 

 comparatively large and appeal- to be opened by the pressnre of the rock 

 matter so as to expose theii- upper surfac(\ They are more or less 

 rounded in foiin and slightly depressed in tlieii' centi'al ])ortions, so as to 

 appear saucer shaped. Xo central colunni, as in Thyrsopteris, was s(>en 

 in the .sori, but the sporangia appear to have been scattered over the 

 whole of their upper surface. The spoi-angia were proportionally (juite 

 large, as the pits left l)y them are to be distinctly seen with the help of a 

 good lens. The pitting caused by the falling out of the sori produces a 

 sort of granulation on the upper surface of the sori. The appearance 

 presented now by the sori on these forms suggests the idea that the>' are 

 compressed so as to open the valves of the involucre, if this existed, and 

 expose the parts contained within thein. 



In some specimens, such as that shown in PI. LXXI, Fig. A, of which 

 an enlarged pinnule is shown in Fig. 4, the metamorphosis of the pinnit; 

 seems to be carried farther and little appearance of a foliaceous nature 

 is shown. These pinna^ are cut down rather more deeply and no differ- 

 ence is shown between the lacinise toward their leases and those higher 

 up. The laciniip are more narrowed and thickened than in Fig. 1 and 

 look like pedicels. They are slightly broader at their summits, where 

 they carry the sori. The narrowed lacinia? with the soi'i look like clubs. 

 These pinna^, so far as seen, are a little less than '.i nnn. wide. They are 

 aliout 2 cm. long and are linear in form. They are inserted on tlie main 

 rachis as inv those shown in PI. LXXI, F'ig. 1, and like them are slightly 

 decuri-ent. The sori bome at the summits of the lacinia' are, in these 

 pimuiles, romided or sometimes slightly reniform. They present a smooth 

 surface* and show more of the indications of sporangia than are to be seen 

 in the forms depicted in PI. LXXI, I'ig. 1. If, as is probable, the sori 

 are furnished with a 2-valved in\olucre, as in Dicksonia, the foi-ms 

 I'epi'esented in ]"ig. 2 show them with the valves closed and exposing 

 only the outer surface of one of the valves. 



