75 



I. 6, the creeping stem; a, basis of a cell; h. Jt, the contractile cord; i, the axial 

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

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



from its cavity, still more strongly magnified. 



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

 axial cord; k. k, the transversal septa. 



PL II. 

 Fig. 1424. Rhabdopleura mirabilis (continued). 



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

 the tentacular arms; e, the oesophagus; f\ the stomach; <?, the intestine; A, the con- 

 tractile cord.' 



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

 c, d, e, f, g, ft, as in the preceding figure; ?, the hyaline semi-lunar border at the 

 basis of the tentacular arms; m, the under lip; n, the ciliated tubercle at the base 

 of the tentacular arm; p, the flexor muscle of the tentacular arm; ^, 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 (,r & y) in process of formation. 

 i, the axial cord; k, 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 side. c. c, the bucal shield; <?, 

 the tentacular arms; h, the contractile cord. 



23. The same polypide together with the axial cord (i) 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* 



