406 PALAEONTOLOGY OF ILLINOIS. 



around it than along its borders ; the rachis of the branches 

 is also thick, smooth, and on both sides of it are attached the 

 groups of sori, three to five in number, in a kind of pyramidal 

 position, with a thick short pedicel in the middle. The sori, 

 when unopened, are round, marked on the flattened surface by 

 four or five lines diverging from the center to the circumfer- 

 ence. Fig. 2a. When opened the sporanges appear placed 

 like the rays of a star around a central point. These spo- 

 ranges, oval, elongated or gradually enlarged outwards from 

 the narrow point of attachment, deeply concave, finely striate 

 within, are all turned to the same side, viz : the point down- 

 wards and the branches tending obliquely upwards ; in that 

 way the upper sori of the pinnae have the point towards the 

 rachis, while in the lowe^ ones it is turned from it : see fig. 2, 

 enlarged twice, and fig. 25, enlarged four times. The spo- 

 ranges are deeply marked or excavated in the stone, which is 

 still more deeply penetrated by the point, and this point appears, 

 as said above, to have been attached to a common pedicel by 

 filaments now destroyed. 



Found in a concretion from Mazon creek; discovered by Mr. M. S. Hall. 



STAPHYLOPTERIS ASTEROIDES, Sp. nov. 



PI. xiv, fig. 6 to 10. 



FROND tripinnate, with straight alternate branches ; primary 

 pinnae lanceolate pointed or tapering to a point from an en- 

 larged base; secondary divisions alternate linear, merely formed 

 of narrow, filiform, obliquely straight branches or common 

 pedicels, bearing groups of sporanges pinnately attached to 

 them in pairs and opposite ; sori round at first and before 

 maturity, opening at maturity in five lanceolate-pointed lacin- 

 iae around a central round point, and forming a star (fig. 7 and 

 7 b enlarged) . 



This fruiting species is still more remarkable than the former. Groups of 

 sori resembling round dots, fig. 8, are seen on the same piece of shale, but on 



