SYSTEMATIC DESCRIPTIONS — CIDAROIDA. 17 



Cidaris texana W. B. Clark (1915, Monograph U. S. Geol. Survey, 

 vol. 54, plate 9, fig. 2b), it is very probable that the test of C. peloria 

 was not less than 60 mm. in diameter and may have been a good deal 

 larger. No other known species in the West Indies, either living or 

 fossil, has spines which approach those of this species either in size 

 or character. In fact, the nearest thing to which it can be compared is 

 the Recent Australian cidarid Phyllacanthus longispinus Mortensen. 

 Mortensen (1918, Kongl. Sven. Vet. Akad. Handl., vol. 58, No. 9) 

 says of this species that a specimen measures 85 mm. in diameter 

 and the longest primary spines measure 105 to 107 mm. in length. 

 Oligocene, marly beds, base of "Arecibo" formation, Government 

 Road, San Sebastian to Lares, km. post 33, Porto Rico, 48 specimens 

 (including the holotype and 4 paratypes which are in the American 

 Museum of Natural History, No. 18564), station 56. Base of "Are- 

 cibo" limestone, Government Road, San Sebastian to Lares, Porto 

 Rico, km. post 33, collected from north side of road from excavations 

 where road-metal has been quarried, 1 specimen, station 58. "Are- 

 cibo" formation, Government Road, San Sebastian to Lares, Porto 

 Rico, shaly limestone, south side of road, km. post 33 (11 km. east 

 of San Sebastian or 5 km. west of Lares), 26 specimens, station 20. 

 Collazo shales, Government Road, San Sebastian to Lares, Porto 

 Rico, near km. post 29, 2 specimens, station 105. The holotype and 

 all of the above paratypes were collected by C. A. Reeds on an expedi- 

 tion of the New York Academy of Sciences, the Porto Rican Govern- 

 ment and the American Museum of Natural History cooperating. 



Cidaris foveata, new species. 

 (Plate 1, Figures 6, 7.) 



The following is a description of this species: 



Test large, flattened dorsally and ventrally. Ambitus below the mid- 

 zone. Ambulacra wide (8 mm.), sunken; poriferous areas wide; pores 

 oval, connected by deep furrows. The interporiferous areas are as wide 

 as a poriferous area, deeply channeled in the median line, elevated on the 

 borders. Interporiferous area ornamented with a series of large tubercles 

 on the outer border of the area on each side, and a second series of smaller 

 tubercles runs parallel to the larger tubercles and just within the same. 

 There are also 2 or 3 miliary tubercles on each plate near the center of the 

 area. The ambulacral areas are quite straight dorsally, but sinuous below 

 the mid-zone. About 12 ambulacral plates equal the height of an inter- 

 ambulacral plate at the mid-zone. Interambulacral plates with large prom- 

 inent tubercles, which are mammillate, perforate, deeply crenulate, with 

 high and wide scrobicular areas which extend dorsally and ventrally nearly 

 to the borders of the plate. A row of secondary tubercles surrounds the 

 primaries, and minute miliary tubercles are abundant toward the middle 

 line of the area on each plate. There are 10 interambulacral plates in a 

 column. The most striking features of the interambulacra and also of 

 the species is a series of deep pits in the median line of each area. These 



