REPORT ON THE ECHINOIDEA. 279 



Fig. 10. Smooth radiole of actinal side. 



,, 1 1. Small radiole surrounding the actinostome. 



,, 12. Specimen of Goniocidaris fiorigera, in which the primary radicles present the 

 usual variation of the tip, especially on the abactinal surface, characteristic of 

 the genus ; natural size. 



,, 12 a. Abactinal area of the same species, partly denuded; magnified. 



„ 13. Portion of denuded test of the same species, facing the median line of an ambu- 

 lacral area ; magnified. 



„ 14. Portion of an interambulacral area of same, from the equatorial zone of test. 



„ 15 o, h. The cupuliform radioles of the abactinal region are seen from above, repre- 

 sented in profile in c, d. (f-). 



„ 16 a, h. End view and profile of a different cupuliform radiole, 15 and 16 are taken 

 from the abactinal region of the test, the principal primary radioles of fig. 1 2 

 are cylindrical (fig. 18), with prominent irregularly-arranged spines scattered 

 over the shaft. 



,, 17. Small radiole of actinal side of test, near the actinostome (f ). 



„ 18. Basal part of shaft of primary cylindrical radioles. 



„ 19. Primary radiole near actinal edge of test. 



,, 20. Tapering spiniferous radiole, similar to those of fig. 7, taken from specimen 

 of fig. 12. 



PLATE II. 



Goniocidaris canaliculata, A. Ag. (figs. 1-18), p. 43. 



Fig. 1. Specimen with long spines, seen from the abactinal side ; natural size. 



,, 2. Specimen -mth short spines, seen from the abactinal side, showing the mode of 

 carrying the young ; natural size. 



„ 3. Another specimen, mth proportionately shorter spines, seen from the actinal 

 side ; natural size. 



„ 4, 5, 6. Portions of the median interambulacral primary plates, to show the variation 

 in the depth of the median interambulacral groove, from a deep broad groove 

 (fig. 4), to a mere indistinct bare space in fig. 5. 



,, 7. Edge of abactinal membrane to show the deep indentation of the median inter- 

 ambulacral and ambulacra! spaces of the test. 



„ 8. Young specimen, 3 mm. in diameter, seen from the actinal side, denuded of spines 

 about in the stage of fig. 12. 



,, 9. Young specimen, seen from the actinal side, 2 mm. in diameter. 



„ 10. The same as fig. 9, seen from the abactinal side. 



