RiTTEE. — Octacnemus. 



PLATE 2. 



Fig. 3. This should be compared with Figure 8, Plate 3. Dorsal view of tlie 

 visceral mass, removed from the test, and a section, part of whicli is 

 shown on its inner surface in Figure 9, Plate 3, cut from the dorsal 

 side of the branchial sac. 



Fig. 4. Same as Figure o, excepting that tlie cut has been somewhat extended, and 

 the food material entirely removed from the branchial sac. 



Fig 5. The stomach-intestine, from the dissection sliown in Figure 4, made by a 

 transverse cut corresponding to tlie line y of Figure 4. 



Fig. 6. A single branchial orifice much enlarged. 



Fig. 7. Tlie endostyle with a portion of the peribranchial band. 



