22 PANAMIC DEEP SEA ECHIXI. 



diameter (PI. 3, fig. 1); they cover proportionally as large an area in the 

 next stage (PI. 3, fig. 2) as in the oldest stage figured (Pi. 3, fig. S). An 

 enlarged part of the madreporic body seen from the exterior is given in 



PI. 4, fig. /,. 



In a specimen 14 mm. in diameter one of the genital plates showed a 

 number of irregular genital openings covered by minute plates (PI. 4, fig. 6). 



In the youngest specimen figured (PI. 3, fig. 1), the five original anal 

 plates can still be seen occupying the angles of the anal system. In the 

 faces of the left anterior, the odd and right posterior interambulacrum a 

 second plate has become intercalated, and the third and fourth sets of plates 

 have made their appearance. In the next stage (PI. 3, fig. 2) there are 

 two intercalated plates on the face of the left posterior interambulacrum, 

 and one on each of the other faces of the anal system ; the intercalated 

 plates and the five original plates forming, as it were, a primary outer cycle 

 with a secondary one of nine plates and a third series of six plates round 

 tlie aujil opening, intercalated in the anal angles of the second row of 

 plate.s. In the next stage (PI. 3, fig. S) the proportions between the anal 

 plates i»av(^ only slightly changed, tho.'^e ol" the second row being propor- 

 ti«)nally large ; otherwise they occupy relatively the same position. 



Dr. Mortensen ' revises the classification of the Cidaridae, radically chang- 

 ing the position of the species among the genera hitherto recognized, 

 and introducing a luunber of new genera based upon minute differences 

 in till? pedicellaria?, and with utter disregard of other characters of the 

 species he groups together. 



As one of the results of his classification, Ci<1am affinis and Dorocidaris 

 jKiplllatit, whicli bad been considered as most closely allied, if not identical 

 species, are now placed in separate genera. There is nothing in the 

 figures of the pedicellarioe given by Mortensen to warrant such a trans- 

 position. Compare his figs. 1 and 7, PI. IX., 21. 23 and 25, 27, for the 

 tri<]entate pcdicellaria\ It seems to be an enormous overestimate of details 

 to consider tiie dilTerences between the glol)iferous pedicellaria? as of generic 

 value. Compare his figs. 17 and 20, PI. IX., figs. 3, 5 and 5, 0; figs. 8. 

 II 'md I.".. !•). lor the globiferous pedicellaritv. The genus Pcfalocidan'^ 

 {G. floritfcra pars) is based upon the small opening of the point of the 

 large globiferous pedicellari«3 (PI. X. figs. 23, 30; 22, 31 ; 10, 11). Only 

 one of the small globiferous pedicellariiv o{ the genus is figured (PI. X. 



* ••Ingolt" Kchinoidca, p. 11. 



