\ 



75 



h. h, the creeping stem; a, basis of a cell: /;. h, the contractile cord; i, the axial 

 cord; L h, one of the septa between 2 chambers of the stem. 

 Fig. 12. The broken end of the axial cord (v) together with the cellular marrow {s) issuing 

 from its cavity, still more strongly magnitied. 



— 13. A piece of the stem with 2 completely closed chambers (obliterated cells) i. i, the 



axial cord; k. Jc, the transversal septa. 



PL II. 



Fig. 14 — 24. Rhabdopleura mirabilis (continued). 



Fig. 14. A piece of a cell with the animal in it, strongly magnified, c, the bucal shield; d, 

 the tentacular arms; e, the oesophagus; /', the stomach; g, the intestine; /t, the con- 

 tractile cord. 



— 15. The animal taken out of the cell and slightly compressed, seen from the left side. 



c, d, c, f, g, h, as in the preceding figure;' 1, the hyaline semi-lunar border at the 

 basis of the tentacular arms; »i, the under lip; v, the ciliated tubercle at the base 

 of the tentacular arm; p, the flexor muscle of the tentacular arm; g, the bucal aper- 

 ture; r, the cellular body between the end ot the intestine and the oesophagus. 



— 16. The anterior part of the body seen from in front, c, d, I, as in the preceding figure. 



— 17. The animal seen from the dorsal side. The letters as in fig. 15. 



— 18. The animal seen from the ventral side. The letters as in fig. 15. 



— 19. A piece of the bucal shield compressed and very strongly magnified, shewing the 



extremities of the muscular fibres, which extend through the substance of the bucal 

 shield, diverging radially. 



— 20. A piece of the creeping stem, shewing 2 polypides (./• <{• y) in process of formation. 



i, the axial cord; h, one of the transversal septa. 



— 21. The earliest stage of development noticed, h, the contractile cord; ?', the axial cord. 



— 22. A further developed polypide, seen from the dorsal si,de. c. c, the bucal shield; rf, 



the tentacular arms; li, the contractile cord. 



— 23. The same polypide together with the axial cord (/) seen from the ventral side. The 



letters as in the preceding figure. 



— 24. The same polypide compressed and more strongly magnified. The letters as in the 



2 preceding figures. 



Fig. 25—30. Flustra abyssicola. 



Fig. 25. The exterior part of a colony, seen from the broad side, about 10 times magnified. 

 a. a, the avicularia. 



— 26. A piece of a colony seen from the narrow side, with the avicularia (a) extended. 



— 27. Another colony of narrower form seen from the broad side. a. a, the avicularia. 



10* 



