68 MESOZOIC AND CENOZOIC ECHINODERMATA OF THE UNITED STATES. 



Pyrina parryi Aguilera, 1893, Datos para la geologfa de Mexico, p. 26. 

 Pyrina parryi Clark, 1893, Johns Hopkins Univ. Circ, vol. 12, No. 103, p. 51. 

 Pyrina parryi Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 59, 60. 

 Pyrina bulloides Cragin, 1893, Geol. Survey Texas Fourth Ann. Rept., p. 162. 

 Pyrina parryi Aguilera, 1897, Inst. geol. Mexico Bol. Nos. 4, 5, 6, p. 215. 

 Pyrina parryi Bos£, 1899, Inst. geol. Mexico Bol. No. 13, p. 11. 



Determinative characters. — Test subpentagonal, broader anteriorly than posteriorly, inflated 

 at the sides, flattened above and below. Ambulacra narrow, uniserial; both areas covered with 

 minute tubercles. 



Peristome large, elliptical, oblique. Periproct oval, supramarginal. 



Dimensions. — Length 20 to 35 millimeters; width 18 to 30 millimeters; height 12 to 25 

 millimeters. 



Description. — The test is regular and symmetrical, slightly pentagonal in outline, enlarged 

 ariteriorally, contracted posteriorly. The upper surface is convex, although somewhat flattened 

 at the summit. The sides are inflated, the base flattened and slightly depressed in the vicinity 

 of the peristome. 



The ambulacra are narrow and lanceolate; the poriferous zones straight and depressed, 

 the pores small, oval, and uniserial. The interambulacra are broad and less elevated than the 

 ambulacra. Both the ambulacra and the interambulacra support numerous small tubercles 

 that are larger and more distinct on the lower than the upper surface. Fine microscopic gran- 

 ules are disseminated between the tubercles. 



The peristome is large, elliptical, and obliquely situated slightly in front of the center of the 

 base. The periproct is oval and placed nearly in the center of the posterior margin. The apical 

 •system is small, composed of four genital plates, the large right antero-lateral modified to form 

 the madreporite. The five small ocular plates are firmly wedged between the ovarial plates. 



Related forms. — The species just described is the only representative of this genus from 

 American strata and both in form and structural features admits of a ready separation from all 

 European species. It presents some points of similarity with Pyrina desmoulinsii D'Archiac, 

 but is broader posteriorly and less elevated. The many specimens of this common species which 

 have come under the observation of the author show considerable variation, but are all regarded 

 as representing a single species. 



Localities. — Leon Springs (type), near San Antonio, Pilot Knob (Travis County), Kent, 

 Sierra Blanca peaks, and many other localities in Texas. 



Geologic horizon. — Fredericksburg and Washita groups, Comanche series, Cretaceous. 



Collections. — U. S. National Museum (9854) ; Johns Hopkins University. 



Family NUCLEOLITIDiE. 



Genus BOTRIOPYGUS D'Orbigny. 



BOTRIOPYGUS ALABAMENSIS Clark. 



Plate XXIV, figures 2a-f. 



Botriopygus alabamensis Clark, 1891, Johns Hopkins Univ. Circ, vol. 10, No. 87, p. 76. 

 Botriopygus alabamensis Clark, 1893, Johns Hopkins Univ. Circ, vol. 12, No. 103, p. 51. 

 Botriopygus alabamensis Clark, 1893, U. S. Geol. Survey Bull. 97, pp. 60, 61, PL XXV, figs, la-f . 



Determinative characters. — Test oblong; more or less depressed on upper surface, highest 

 anteriorly; under surface concave. Ambulacra broad, lanceolate; poriferous zones subpetaloi- 

 ial above. Interambulacral plates covered with numerous, irregularly distributed tubercles. 

 Aoical system anteriorly situated. Peristome small, oblique, forward of the center. 



Dimensions. — Length 63 millimeters; width 54 millimeters; height 26 millimeters. 



Description. — The single imperfectly preserved specimen of this species, although apparently 

 lacking some of the characteristics of Botriopygus, is nevertheless referred to that genus. The 

 test is oblong, considerably depressed on the upper surface, and concave on the base. The apex 



