134 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



of the odd anterior ambulacral depression to the peristome, 

 near which it becomes deeper, is present on the under side. 

 Peristome, large, semi-circular, and with prominent posterior 

 labrum which merges posteriorly with the amphisternum. 

 Periproct large and supramarginal. A sinuous peripetalous 

 fasciole is present; also a broad, distinct, cordate, subanal 

 fasciole. Prominent perforated tubercles, limited by the peri- 

 petalous fasciole on the upper surface, are present on the pos- 

 terior plates of the interambulacra ; odd posterior interambu- 

 lacrum not shown in the specimen at hand. On the under 

 surface the tubercles are large and for the most part uniform 

 in size, but are slightly smaller on the amphisternum; those 

 enclosed by the subanal fasciole are arranged in radiating 

 rows; smaller primaries are present on the interambulacral 

 plates adjacent to the odd ambulacrum. The remainder of 

 the surface is covered with secondaries and granules. 



Geologic Horizon: — Upper Oligocene or Lower Miocene. 



Type: — No. 371, Cal. Acad. Sci. 



Type Locality: — X23 (Rio Bravo Oil Company's number), 

 twelve miles east of San Rafael on Zarizal River, where the 

 salt water joins the fresh. Colls., Prof. W. F. Cummins and 

 Mr. Sands. 



Named for Professor W. F. Cummins. 



Macropneustes mexicanus, new species. 



Plate 24, fig. 3 ; plate 25, figs, la, lb. 



Test of large size (anteroposterior diameter, 76.4 mm. ; 

 transverse diameter, 68.9 mm.; greatest height, 34.8 mm.); 

 tumid and with rounded margin. Marginal outline suboval, 

 slightly angulated, broader and more rounded in the anterior 

 part; posterior end truncated; broad shallow groove in the 

 odd anterior ambulacral area. Ambulacra and interambulacra 

 of varying widths at the ambitus ; odd anterior one, very nar- 

 row; lateral paired areas of equal widths, being about one- 

 half that of the posterior paired interambulacra; anterior, 

 paired interambulacra narrower and with the plates adjoining 



