52 GINKGOALBS [CH. 



the axis is 2-3 cm. long and some microsporangia are seen in their 

 original position, while others are detached^. It is by no means 

 unlikely that these specimens are portions of male flowers of 

 GinJcgoites digitata or of some other species, but this cannot be 

 definitely settled until better material is available. Some Rhaetic 

 fossils described by Nathorst^ as Antholithus Zeilleri present a 

 certain resemblance to these supposed male flowers. One of 



Fig. 654. Antholithus sp. (Sedgwick Museum, Fig. 655. Antholithun Zeilleri. 

 Cambridge; A, ca. X U; B,ca. X 2.) A, drawn (After Nathorst; x2f.) 



by M. Seward ; B, drawn by L. D. Sayers. 



Nathorst's specimens from Scania is reproduced in fig. 655 twice 

 natural size; the photograph, for which I am indebted to Prof. 

 Nathorst who published it in 1908, shows a cuticular preparation 

 of the axis and microsporangia. The axis of Antholithus is 

 dichotomously branched and bears terminal clusters of micro- 

 sporangia about 3-5 mm. long, usually eight in a cluster ; several of 

 them have dehisced longitudinally and the apices show a slight 

 separation of the two halves. In some of the sporangia Nathorst 

 found microspores with an average length of 40 — 43 /x agreeing 

 closely with the spores of Ginkgo and recent Cycads. Nathorst 

 considered that Antholithus Zeilleri may be a male flower of some 

 Ginkgoaceous plant though a correlation with a Cycadean bype is 

 by no means excluded. There is, however, a general resemblance 

 between the EngHsh Jurassic specimens shown in fig. 654 and the 

 Rhaetic species ; the latter is distinguished by a greater tendency 



^ Seward and Gowan (00) B. PI. ix. fig. 28. 

 2 Nathorst (08) p. 20, PI. iv. 



