1895.] On the Development of Lichenopora verrucaria. 



73 



microsomes. They always form part of the cytomitoma, and are 

 therefore plasmatic, and not paraplastic. They are probably con- 

 cerned with amoeboid movement, and they and the rest of the 

 mitoma are more visible the more active the cell. No definite con- 

 clusions as to their chemistry can yet be arrived at, bnt all the altered 

 microsomes probably consist of nucleo-albumins, the basophiles being 

 richer in phosphorus than the eosinophiles. 



In diseased conditions it is probably impossible to say what organ 

 is affected from the kind of leucocytes present in excess in the 

 blood. 



VI. " On the Development of Lichenopora verrucaria, Fabr." By 

 Sidney F. Harmer, M.A., Fellow of King's College, Cam- 

 bridge, Superintendent of the University Museum of 

 Zoology. Communicated by A. Sedgwick, F.R.S. Received 

 October 15, 1895. 



(Abstract.) 



The principal results of my examination of the life-history of 

 Lichenopora have already been communicated to the Royal Society.* 

 I then showed that embryonic fission occurs as a normal process in 

 the development of that genus, as of Grisia. The general growth of 

 the colony and of the embryo was described, and attention was 

 called to the remarkable fact that the embryonic processes which 

 culminate in tbe production of the entire first brood of larvae com- 

 mence in the earliest stage of the formation of the colony itself. 



The present paper contains a fuller account of the processes 

 indicated above, with the addition of some new details. Statistics 

 are given to show that the zocecium which produces the primary 

 embryo, from which the larvae are developed by a process of em- 

 bryonic fission, is, in the great majority of cases, one of the first two 

 blastozoites of the colony. The position assumed by these two 

 zooecia depends on the direction in which the primary zocecium has 

 become curved ; and " left-handed " and " right-handed " colonies 

 are accordingly distinguished. The relation of the young ovicell to 

 the fertile zocecium has been observed for the first time. The forma- 

 tion of the ovicell commences with the occlusion of the orifice of the 

 fertile zocecium ; and this takes place in such a way that the body- 

 cavity of the zocecium remains continuous, near the orifice, with the 

 cavity of the ovicell. The polypide has previously degenerated, and 

 the embryo, contained in an investment, the " embryophore," has 

 passed up to the neighbourhood of the orifice, still attached to the 



* ' Roy. Soc. Proc.,' vol. 57, p. 188. 



