2 PROCEEDINGS OF THK NATIONAL MUSEUM vol. 07 



Paleontology''^; while the general aspect of the fossil is illustrated 

 on page 231 by their copy of D'Orbigny's restoration, incorrect as 

 to cirri, of his well known species, A. roissyanus; also in Dana's 

 Manual of Geology." 



While remains of five other important European Mesozoic genera, 

 Pentacnnus^ Isocrinus, Balanocrinus^ Bourgueticrinus^ and Mar- 

 sufitcH^ liave been identified in Amer^a, the extremely prolific Afio- 

 crinuH has remained until this time unrepresented in the western 

 hemisphere. I am now able to announce its addition to the list. 



Jn March, 1023, ISIr. W. S. Adkins brought into the United States 

 National Museum in Washington a series of fossils collected by him 

 in the course of geological investigations for the T^ia. IMexicana de 

 Petroleo '' P^l Aguila '" on the isthmus of Tehuantepec, Mexico. 

 Among them Avere a number of crinoid stem-fragments which were 

 submitted to me for examination. Some of these were in the matrix, 

 a pinkish limestone, and others loose. They were derived from a 

 limestone outcrop on the east baiik of tlie Eio Playas at a point 10.8 

 kilometers soutli and 3.9 kilometers east of the northeast corner of 

 the Limantour property, near the junction of the rivers Playas and 

 Potrero Nuevo. The horizon was identified by IMr. Adkins, on the 

 strength of the other fossils, as upper Jurassic or lower Cretaceous, 

 proba!)ly the former, wliich the evi^lence of the crinoids confirms. 



The crinoid stems are in small sections, none of them containing 

 more than eight or ten columnals. In several the joint-faces are 

 well expo.sed, and inspection of them at once eliminated Pentacrinus. 

 and BaJanocrinus from consideration, while it disclosed a similarity 

 of type to the joint-faces of Apiocrinus, which was confirmed by the 

 presence of a single piece containing five columnals having the char- 

 acteristic expansion of the stem proximal to the calyx. This left no 

 doubt as to the generic affinity of the fossils, thus establishing for 

 the first time the existence of Apiocrlnus in the rocks of the Ameri- 

 can continent. While the material is too imperfect for close specific 

 discrimination, the occurrence is of sufficient interest paleontologi- 

 call}^ to warrant the designation of a new species, for which I pro- 

 pose the name — 



APIOCRINUS TEHUANTEPEC, new species 



There are about 20 stem-fragments, similar in appearance and 

 evidently belonging to the same species; all are round, and without 

 trace of cirri, the largest about 10 mm. in diameter. The tapering- 

 specimen is the most characteristic. Its five columnals have a total 

 length of 13 mm., and during that interval it enlarges from 7 mm. 

 to 10. Tlie joint-face is marked by about 56 fine radiating striae 



2 1913 edition, i>p. 230. 231. ^ FourtJi wlition. p. 778. 



