110 CONIOPTEEIS. 



PI. XXI. Figs. 3 and 3a. Leckenby Collection, Cambridge. 



The specimen represented in Fig. 3 is shown about twice natural 

 size ; the pinna measures 2*7 cm. in length. Some of the fertile 

 segments are exactly like those of PL XVII. Figs. 6 and 8, and 

 identical with Tympanophora racemosa, L. & H. ; the upper fertile 

 segments, which are more reduced and have only one large cup- 

 shaped sorus, subtended in some cases by a short bract-like sterile 

 lobe, agree with the form referred to Tympanophora simplex. 

 Another feature of interest is the same long and narrow division 

 depending from the lowest pinnule as in the specimen shown in 

 Figs. 1 and 2. 



Fig. 3a shows a single enlarged sorus with indications of 

 sporangia. Cf. Thyrsopteris Murrayana as figured by Heer. 



52,550. PL XXI. Figs. 4 and 4. 



Part of fertile pinna, drawn twice natural size. The chief 

 interest of this fragment is that the pinnules are only partially 

 fertile ; instead of a much reduced fertile segment with little or 

 no lamina, we have pinnules of the ordinary sterile form bearing 

 one or two marginal sori. The lowest pinnules have the same 

 Aphlelia-liL&e appearance more obvious than shown in the figure 

 as in Figs. 1, 2, and 3. 



Fragments of pinnae of the form illustrated in both Figs. 1 and 2 

 of PL XX. occur in close association with that of Fig. 4, PL XXI. 

 The manner of occurrence of a sorus is more clearly shown in 

 Fig. 4a. 



V. 3289. Several detached pinnae on an iron-stained sandstone ; 

 these furnish examples of both the more rounded and the more 

 pointed pinnules, and may be matched equally well with the 

 pinnae represented in Figs. 4 and 5, and with that shown in Fig. 6. 



Yorkshire Coast. Purchased. 



V. 3680 and V. 3681. Pinnae with pinnules varying much in 

 size, some being as large as those of Fig. 5, PL XVI. (52,568) and 

 others like the lower branches of the frond represented in PL XX. 

 Fig. 1. Such examples as this serve to connect Thyrsopteris 

 Maakiana, Heer, on the one hand, and Sphenopteris hymenophylloides, 

 Brongn., 8. arguta, L. & H., on the other. 



