286 THE VOYAGE OF H.M.S. CHALLENGER. 



Fig. 9. One of the pedicellarise which arc common along the edge of the test along the 

 line of the miliaries. 



PLATE XL 



Phormosortia hoplacantha, Wy. Thom. (figs, 1-4), p. 10 L 



Fig. 1. Segment of test seen from the abactinal side ; half natural size (312 mm. in 



diameter). 

 „ 2. Segment of same seen from the actinal side. 

 „ 3. Abactinal system covered with spines. 

 ,, 4. Part of abactinal system denuded, to show the large anal plates separating the 



plates of the genital ring (2). 



PLATE XIL 



Phormosoma hoplacantha, Wy. Thom. (figs. 1-4), p. 101. 



Fig. 1 . Half of test seen in profile ; same specimen as that figured on Plate XL (half 



natural size). 

 ,, 2. Segment of test seen with the actinal floor removed, to show the position of the 



ovaries and of the mesenteries separating the ovaries from the poriferous 



zone. 

 „ 3. Same, seen from the interior to show the mode of imbricating of the buccal plates ; 



they la]D away from the actinostome (f ). 

 ,, 4. Part of actinal system denuded to show the arrangement of the buccal plates (f ). 



PLATE XIP. 



Young Echinothuridse (figs. 1-9), p. 71. 

 Fig. 1. Phormosoma rigid urn, A. Ag., seen from abactinal side (^^). 

 ,, 2. Abactinal system of same still further enlarged (f). 

 ,, 3. Segment of actinal surface of test of same (f ). 

 ,, 4. Segment of abactinal surface of test of same (f ). 

 ,, 5. Abactinal system and segment of test of young Asthenosoma gracile, A. Ag. (f ), 



24 mm. in diameter. 

 ,, 6. Segment of actinal surface of same. 



„ 7. Abactinal system oi Phormosoma asterias, measuring 30 mm. in diameter (f). 

 ,, 8. Segment of actinal surface of same (f ). 

 „ 9. Segment of abactinal surface of same (f). 



