‘ PORCUPINE ’ DEEP-SEA DEEDGING-EXPEDITIONS. 753 
Fig. 3. A portion of the ventral part of the test, seen from within, x 2. 
Fig. 4. The apical plates and the periproct, seen from within. X 2. 
Fig. 5. The outer aspect of a portion of the apical surface of the test. X 2. 
Fig. 6. Inner aspect of the same, x 2. 
Fig. 7. A cribriform plate from the wall of one of the tube feet. X 60. 
Fig. 8. Appearance of a thin slice of one of the plates of the perisom under a low power. 
Calveria fenestrata, Wy. T. 
Fig. 9. A pair of tooth-sockets, showing the form of the epiphyses. 
Fig. 10. Lateral view of the same. 
PLATE LXIV. 
Calveria hystrix , Wy. T. 
Fig. 1. Natural size. 
Fig. 2. Portion of one of the large spines, x 30. 
Fig. 3. One of the tube feet from the ventral surface of the test. X 30. 
Fig. 4. A large tridactyle pedicellaria. X 30. 
Fig. 5. One of the smaller tridactyle pedicellariae. X 50. 
Fig. 6. An ophiocephalous pedicellaria. x 50. 
PLATE LXV. 
Calveria hystrix. 
Fig. 1. Outer aspect of a portion of the test of the ventral surface. X 2. 
Fig. 2. The same, seen from within. X 2. 
PLATE LXVI. 
Calveria fenestrata, Wy. T. 
Fig. 1. Plates of the apical disk, from within. X 2. 
Fig. 2. The external surface of the same. X 2. 
Fig. 3. The test opened to show the arrangement of the fasciae which enclose the ambu- 
lacral organs and the position of the ovaries. X 2. 
Fig. 4. The test thrown back to show the mesenteric membranes and fibres which 
suspend and retain in position the coils of the intestine. X 2. 
Fig. 5. A portion of a series of ambulacral plates, showing the arrangement of the 
ampullae and the distribution of the branches of the ambulacral vessel to the 
pores. 
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