PRELIMINARY NOTE ON THE NERVOUS SYSTEM 

 OF THE GENUS CYPRIS. 



[ With Plates III and IF.] 



By C. H. Turner. 



Some time ago I began to collect material for a study of 

 the histology of the Ostracoda. The work is progressing, but, 

 owing to]delays in obtaining material, it will be a year or more 

 before the work is completed. This being the case and since, 

 so far as I have been able to discover, no work has been 

 published on the histological neurology of the fresh-water Os- 

 tracoda, it is thought that a preliminary note on the nervous 

 system of Cypris will not be an unwelcome contribution to 

 Biology. Since it is intended, in the final paper, to give a 

 resume of all the histological papers that have been published 

 on the Ostracoda, no bibliographical list is given in this note : 

 however, comparisons will be made between the nervous sys- 

 tem of Cypiis and that of the other forms that have been de- 

 scribed. For a similar reason, it is not considered necessary 

 to give an account of the technique involved. The following 

 remarks are based chiefly on a study of Cypris Jierticki, but 

 sections of other members of the genus have been used for 

 comparison. 



The nervous system of Cypns agrees with that of other 

 Crustacea in being composed of a compound supra-cesophageal 

 ganglion and a multi-ganglionic ventral chain. 



The supra-oesophageal ganglion [fig. 9] or brain lies much 

 nearer the dorsal than than the ventral surface of the body and 

 lies cephalad of the foregut. This is a compound structure, 

 being composed of at least three sets of ganglia. These sets 

 are : the optic ganglion, the antennulary ganglia and the cere- 



