REPORT ON THE ECHINOIDEA. 293 



Catojyi/gus recens, A. Ag. (figs. 17-21), p. 123. 



Fig. 17. Petaloid ambulacra of Catopygus recens (■^^)- 



„ 18. Catojyi/gus recens, seen from the abactinal side ; natural size. 



„ 19. Same, seen from the actinal side. 



„ 20. Same, seen from the anal extremity. 



,, 21. Same, seen in profile. 



PLATE XX^ 



Hemiaster cavernosus, A. Ag. (figs. 1-22), p. 177. 



Fig. 1. Female, seen from the abactinal side, showing the mode of carrying the young 



in the deeply-sunken petaloid ambulacral areas. 

 „ 2. Single petal, with the young less advanced than in fig. 1 (f ). 

 ,, 3. Test, seen from the actinal side (large male). 

 „ 4. Large male, seen from the abactinal side, to show the petaloid ambulacra slightly 



sunken below the general level of the test. 

 Figs. 1, 3, 4, all somewhat enlarged {^)- 

 „ 5. Interior view of abactinal part of test, showing the narrow, slightly swollen 



petaloid ambulacra of a male ; natural size. 

 „ 6. Same view of a female, showing the broad, swollen petaloid ambulacra ; natural 



size. 

 „ 7. Young Hemiaster, taken from the pouch of the petaloid ambulacra, still some- 

 what circular with straight primary spines, seen from the abactinal pole ; 



natural size, 2 mm. 

 „ 8. Somewhat older Hemiaster, with curved primary spines, seen from the abactinal 



pole ; natural size, 3 mm. 

 „ 8 a. Three spines of fig. 8 ; magnified. 

 „ 9. Young Hemiaster. about in condition of fig. 8, denuded of spines, showing the 



simple ambulacral pores, the large anal opening within the peripetalous 



fasciole, and the ring of large primary tubercles, forming its imier edge ; 



magnified. 

 „ 10. The same, somewhat less magnified, seen from the actinal side. 

 „ 11. Section through a young lZem{as^er of about this stage, showing the course of 



the alimentary canal. 

 „ 12. Magnified view of portion of the test of fig. 9, showing a part of the ambulacral 



and interambulacral systems and a piece of the peripetalous fasciole. 

 „ 13. Young Hemiaster, measuring 5-5 mm. ; the anal system is just beyond the edge 



of the broad peripetalous ftisciole, seen from the abactinal side. 



