XXXIX] OTOZAMITES 537 



the angle varies considerably in different parts of a frond 

 (fig. 602) ; apices generally tapering to a point, or more or less 

 obtusely rounded; veins numerous, parallel, and not as a rule 

 prominent. It is by no means unlikely that specimens figured 

 by Goeppert 1 and some other authors as Pterophyllum saxonicum 

 or Dioonites saxonicus are examples of this species. Fontaine 2 

 speaks of Dioonites Buchianus as one of the most widely distributed 

 and characteristic members of the Potomac flora and it is de- 

 scribed from Japan by Yokoyama 3 and Nathorst 4 . This type 

 appears to be especially characteristic of Wealden strata. 



OTOZAMITES. Braun. 



Braun 5 proposed the name Otozamites for certain Mesozoic 

 fronds formerly included in Zamites, one of his types being 

 Otozamites obtusus (Lind. and Hutt.) (fig. 603, B) originally regarded 

 by Brongniart as a Fern and named Filicites Bucklandi*. The 

 auriculate form of the base of the pinnae and the spreading veins 

 were emphasised in the definition of the genus. As in the case 

 of many other Cycadean fronds the limits of the genus are not 

 always easy to define, but as described below the genus is on the 

 whole fairly distinctive. It is a very widely spread Jurassic 

 type and extends from Triassic to Lower Cretaceous rocks. The 

 supposed Cretaceous species from Greenland, 0. groenlandica 

 Heer 7 , is probably not a plant-impression but a polished groove 

 in the rock. 



Fronds pinnate, reaching a length of 50 cm. or more in some 

 species; pinnae alternate, separate or contiguous and imbricate, 

 attached by a portion of the base to the upper surface of the 

 rachis, long and narrow (fig. 603, A), broadly oval or almost 

 orbicular, apex acute or obtuse, base auriculate and asymmetrical 8 , 

 the anterior lobe being more prominent than the posterior edge 

 of the lamina which is usually rounded. The veins radiate from 

 the base and pass obliquely with occasional branching to the 



Goeppert (47) PL xxxvm. 



Fontaine (89) B. p. 182, Pis. LXVIH. LXXIV., etc. 



Yokoyama (94) p. 223, Pis. xx., xxm., etc. 



Nathorst (90) A. Pis. n., in., v. 



Braun in Miinster (42) B. p. 36. 6 Seward (95) A. p. 56. 



Heer (75) n. PL xxvi. fig. 2; the specimen is in the Stockholm Museum 



HaUe (13 2 ) p. 55. 



