CLYPEASTER EUROPACIFICUS. 27 



Clypeaster ravenelii. 

 s 



Stolonoclypus ravenelii A. Agassiz, 1S09. Bull. M. C. Z., 1, p. 26o. 

 Clypeaster ravenellii A. Ap:assiz, 18S3. Mem. M. C. Z., 10, p. 43. 



Plates 122, figs. 13-14; 123, figs. S-W. 



\u liis account of the Blake Echini, Mr. Agassiz gives very satisfactory 

 figures of this species; I have given here some additional figures to show the 

 spines and pedicellariae. By an unfortunate misprint on p. 42 of his Blake 

 report, Mr. Agassiz says that PI. XF of the Revision represents this species; 

 that plate illustrates details of structure in the test of C. rosaceus. Apparently 

 Mr. Agassiz intends to refer to PI. XP' where there are two figures of a Clypeaster, 

 labelled "subdepressus," which resemble ravenelii to a certain extent, but which 

 really represent C. prosiatus Ravenel, a species Mr. Agassiz considered synony- 

 mous with subdepressus. The type of ravenelii, a young specimen, was taken 

 among the Florida Keys; the Blake took specimens on the Yucatan Bank, 

 Gulf of Mexico; near the Danish West Indies; and off Montserrat, Grenada and 

 St. Vincent. The depths were 34-124 fms. The largest specimen is 132 mm. 

 long, 13() mm. wide and 36 mm. high.; the concavity of the posterior side is 

 4 mm. The original type specimen is only 40 X 40 X 7 mm. 



Clypeaster europacificus,i .sp. nov. 

 Plates 123, figs. 13-16; 129; 130; 131; 136, fig. 1. 



Length from distal margin of unpaired ambulacrum to distal margin of 

 posterior interambulacrum, 165 mm.; greatest breadth, just posterior to antero- 

 lateral ambulacra, 165 mm.; height, mouth to apex, 40 nun. Form pentagonal, 

 with sides deeply concave; posterior side has the concavity 12 muL deep; 

 margins rather thin, about 7 mm. or not quite .06 test-length. Test highly 

 arched in middle but rather flat distal to petals. Tuberculation of test rather 

 coarse or better rather sparse; primary tubercles very small, with sunken areolae, 

 about eighty per sq. cm. of test surface aborally; ridges between pore-pairs of 

 unpaired petal, with a single series of seven or eight primaries; miliary tubercles 

 fairly numerous, about ten times as many as primaries but not closely crowded. 

 Madreporite pentagonal (in other specimens circular) with ocular plates and 



' Eiirmis = rastorn + pacifiru.'--, in allii.sion tn its grographiral (H.^tribution. 



