56 STUDIES IN GEOLOGY, No. 4 



CYCADOPHYTA 



Genus OTOZAMITES Braun 



[in Miinster, Beitr. Petrefact. hft. 6, p. 36, 1843] 



This form genus, proposed by Braun in 1843, was diag- 

 nosed in the following terms: Leaves pinnate, pinnae alter- 

 nate and approximate, auriculate, and attached by a portion 

 of the base; veins radiating from the point of attachment 

 to the margins of the segments. 



Its proposer included in it Odontopteris falcata Sternberg, 

 Filicites Bucklandi var Brittanica of Brongniart and Zam- 

 ites brevifolius, the first two being forms which Morris in 

 1841 had assigned to the genus Ptilophyllum. Brongniart 

 (Tableau p. 61) adopted Braun's genus and pointed out that 

 it corresponded to Otopteris Lindley & Hutton. 



There was at that time much difference of opinion as to 

 whether these forms were cycads or ferns and even as 

 recently as 1895 Seward deems it necessary to remark (Jur- 

 assic Fl. pt. 2, p. 59) that we know very little regarding the 

 exact botanical position of the genus. If by this is meant 

 that its exact relations to other frond genera of the Mesozoic 

 cycadophytes is not definitely determined, the statement is 

 undoubtedly true. No competent student would at the pres- 

 ent time deny that it was a cycadophyte. 



The question of the auriculate base something not seen in 

 recent cycads is one that is not always easy to determine in 

 forms with such thick stipes and overlapping pinnae pre- 

 served as impressions, except in cases where the preservation 

 is unusually good. Brongniart suggested Sphenozamites for 

 forms of the same general type as Otozamites but lacking 

 auricules, and this genus has been rather generally adopted. 

 Bornemann published an amplified and amended diagnosis of 

 Otozamites in 1856 in which he emphasized the distal auri- 

 cles which are exaggerated in some species, his definition 

 demanding the attachment of the pinnae near their proximal 

 basal border, a variable and untenable category. 



