PLATE XVT. 



PAGE 



Fig. 1. Esperella nuda, portion o{ sipecimen ; natural size, . . . 70 



Fig. 2. Esperella lapidiformis ; x f , . . . . , .64 



Fig. 2a. Vortical section of same, showing the position of the embryos (^) ; x i. 

 Fig. 2&. Portion from toj") of same, shomng oscula (0) ; natural size. 



Fig. 3. /op/ion cMi/(^r (Station 145); natural size, . . . .119 



Fig. 4. lophoti. ci/lindricus ; natural size, . . . . .120 



Fig. 5. Esperella porosa; the soft parts have been removed from the lower half of 



the sponge, showing the fibre ; o, oscula ; natural size, . . 69 



Fig. 6. /op/iow /amma/?*-, portion of specimen ; natural size, . . .121 



Fig. 7. Esperella geJatinosa ; 0, osculum ; natural size, . . . .66 



Fig. 8. Esperella arenico/a , ) )ortion of upper surface ; o, oscula ; natural size, . 72 



