the ('ape CeplutloJiscus. 243 



9. The method of feeding is that particles are carried by- 

 means of these cilia to the arms, where a selection is 

 made of the food-particles, which are returned to the 

 mouth by the grooves in the arms. 



10. The zooids and buds are black in the living condition, 

 • but the colour dissolves out very quickly in preser- 

 vation. 



11. The eggs are enclosed in a capsule, which is adherent 



by one end to the wall of the tube. 



12. The embryo is ciliated and coloured at an early stage, 



the older embryos being folded on themselves. They 

 rotate actively in the egg-capsule. 



13. The free larva is elongate, ovoid, and usually narrower 



posteriorly, where an indentation is usually seen. 



14. An apical sense-organ appears early in the embryo, and 



is present in the larva in the form of a white area 

 surrounded by a dark ring of pigment-spots. 



15. The larva is uniformly ciliated, and progresses actively 



over the surface on which it occurs. It is not free- 

 swimming, and rapidly sinks to the bottom when placed 

 in the water. It secretes a viscid substance, by means 

 of which it adheres somewhat securely to the sub- 

 stratum. The ventral surface has a thickened foot- 

 like area. 



References. 



(i) Gilchrist, J. D. F. "New Forms of the Hemichordata from 

 8. Africa." Trans. Phil. Soc. S. Africa, vol. xvii. pt. 2. 1908. 



(2) Harmer, S. F. "The Pterobranchia of the 'Siboga' Expedition, 



■with an Account of other Species." Resultats des Explorations 

 a bord du ' Siboga/ Monogr. xxvi. bis. 1905. 



(3) PiIDEWood, W. G. "Pterobranchia: Cephalodiscus." Nat. Ant. 



[' Discovery '] Exped. Nat. Hist. vol. ii. Publ. by the Brit. Mus. 

 1907. 



(4.) . " A new Species of Cephalodiscus ( C. gilchrisli) from the 



Cape Seas." Mar. Inv. S. Africa, vol. iv. 190S. 



Appendix. By Sidney F. Harmer, Sc.D., F.R.S. 



The manuscript of the paper printed above was forwarded 

 to me by Dr. Gilchrist in a letter dated May 12, 1915, with 

 the request thac 1 would arrange for its publication. Species 

 of Cephalodiscus have so seldom been observed in the living 

 condition that the observations recorded cannot fail to be of 

 interest. 



l)r. Gilchrist states in his letter that he has been unable 

 to refer to some of the recent literature, and in particular to 



