Z PROCEEDINGS OF THE NATIONAL, MUSEUM vol.76 



Probably upper middle Eocene, Guayabal formation. 



I), jperpusilla, new species. 

 Probably upper Eocene, Tepetate formation (Lower California). 



D. clojJtoni, new species. 

 Eocene, horizon not reported. 

 B. 'palenquensis, new species. 



Previously no lower Eocene species of Discocyclina have been de- 

 scribed from America, except D. cristensis (Vaughan). Three species 

 and one variety are here described. Two of these species exhibit inter- 

 esting features. D. weaveri possesses an embryonic apparatus in which 

 the second chamber almost entirely surrounds the first and the first 

 two chambers are nearly surrounded by a ring of chambers larger than 

 the succeeding equatorial chambers. D. cristensis was first described 

 by me as doubtfully belonging to the genus Orhitoclypeus Silvestri (for 

 references to literature, see p. 8 of this paper). The second chamber 

 of its embryonic apparatus is reniform, but the first two chambers 

 are surrounded by a ring of chambers that differ from the later formed 

 equatorial chambers. It appears that D. weaveri and D. cristensis 

 may represent an early stage in the development of Discocyclina. 

 D. cristensis is associated with a new genus and species which I have 

 described as ActinosipJion semmesi in a recent number of the Journal 

 of Paleontology (vol. 3, p.—, 1929). 



Discocyclina perpusilla is peculiar in that the annular siphon 

 between the chambers of the same ring is situated next the distal 

 instead of next the proximal wall of the chambers. Under the de- 

 scription of this species are recorded the results of experiments to 

 impregnate the open spaces of a test with boiling balsam and 

 subsequently to decalcify it with acetic acid, according to the method 

 employed by Hofker. There was no evidence of any canal system. 

 The dark lines usually seen in both the radial and annular walls of 

 Discocyclina look suggestively like the canals in Cycloclypeus, and 

 canals have been described by Ehrenberg and Carpenter. My 

 experiments appeared to be against the presence of canals, but I 

 should perhaps not be warranted in denying their presence. Should 

 Discocyclina be shown to have a canal system, it would have to be 

 removed from the Orbitoididae. 



Discocyclina cloptoni is peculiar in that the two initial chambers 

 are often doubled, trebled, or quadrupled, producing four, six, or 

 eight, instead of only two chambers. 



The other four species apparently present no noteworthy diver- 

 gence from the usual generic features of Discocyclina. 

 AMERICAN SPECIES OF DISCOCYCLINA 



In my paper on "American and European Tertiary Larger Foram- 

 inifera"^ I summarized knowledge of the American species of the 



» Geol. Soc. Amer. Bull., vol. 35, pp. 785-822, pis. 30-36, 1924. 



