On Ceratopora, the Type of a New Family o f Alcyonaria. 195 



cells of the implanted portions of tumour ceased to proliferate at an earlier 

 period, and were no longer living after the expiration of five days. 



In conclusion I must express my indebtedness to Dr. Wakelin Barratt for 

 the assistance he has given throughout the course of this work. 



Summary. 



1. Portions of human carcinoma implanted into animals were observed 

 during the first five days to retain their vitality and to exhibit mitoses after 

 implantation. 



2. After the expiration of this period no evidence of vitality was observed. 



3. Mitosis was markedly inhibited within 24 hours of implantation, whilst 

 the life of the implanted cells was abolished less rapidly. 



On Ceratopora, the Type of a Neiv Family of Alcyonaria. 

 By Sydney J. Hickson, F.E.S., Professor of Zoology in the University of 

 Manchester. 



(Received June 15 —Read June 29, 1911.) 



[Plate 6.] 



In the introduction to the British Museum Catalogue of the Jurassic 

 Bryozoa (1896), Gregory remarks that, " to the palaeontologist, who cannot 

 check his conclusions by the evidence of vascular anatomy or embryology, 

 these tube-dwelling animals are a vexation and a puzzle." This passage 

 has reference to the difficulties that the palaeontologist meets in determining 

 the proper systematic position of many fossils that are known to us only 

 by the tubular skeletons that they have left deposited in the rocks. 

 Simple or colonial tubular skeletons, or more correctly shells, may be 

 formed for the protection of recent sedentary animals belonging to the 

 Protozoa, Ccelenterata, Annelida, Polyzoa, and Mollusca, and in many 

 cases the only trustworthy guide to their systematic position is to be 

 found in the study of the soft structures that formed the shell, the shell 

 itself affording no distinctive characters. 



In some cases the presence of septa, and in others of tabulae, may indicate 

 affinities ; but even these characters may be misleading and give rise to 

 erroneous conclusions. The presence of septa — now called pseudosepta — 



