ON THE OCCURRENCE OF AN APUS IN THE PERMIAN 

 OF OKLAHOMA 



RUDOLF RUEDEMANN 



New York State Museum, Albany, N.Y. 



Professor J. W. Beede last year sent two specimens of a crus- 

 tacean from the Permian of Oklahoma to the New York State 

 Museum for investigation. They were from a suite collected by 

 Dr. Thomas T. Jackson in a thin sandstone bed of the Enid forma- 

 tion, exposed "on the top of a hill four or five miles north of Elkeno, 

 Oklahoma." 



The specimens^ proved, on inspection, of exceptional interest 

 for the reason that they not only exhibit an outline of the carapace 

 as seen in Apus but even the impressions of the "shell-glands" 

 or excretory organs in a form as it is today known in Apus, and its 

 close relative Lepidurus. We have, therefore, no hesitation in 

 considering this Permian form a true Apus, and propose for it the 

 name Apus beedei sp. nov. 



Apus beedei sp. nov. 

 Description. — Carapace small (the larger specimen 15 mm. X 

 14 mm.) ; broadly elliptic, nearly circular in outline, with a small 

 posterior emargination; shieldlike and sloping from the subcentral 

 apex abruptly forward, more gently backward, and probably 

 originally fairly steeply toward the lateral margins. A transverse 

 cervical fold is situated about one-fifth of the length of the carapace 

 posterior to the anterior border. Immediately posterior to this 

 are the large but slightly curved "shell-glands" or excretory 

 organs; beginning at either side of the median line they extend 

 obliquely backward about midway of the lateral faces of the 



^ Professor Beede had stated in his letter that he had more specimens than the two 

 sent but none showing features not seen in the ones inclosed. On inquiry, we learn 

 that this further material is not available at present, but in view of Professor Beede's 

 statement and the great interest of the material, we venture to publish this notice 

 without having had access to the less favorably preserved specimens. 



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