F. S. CON A NT ON THE CUBOMEDUS^E. 57 



thing as the big multipolar ganglion cells with large nucleus and 

 nucleolus which lie in about the same region and were correctly described 

 and figured by Claus but are not specially mentioned by Schewiakoff. I 

 cannot agree with Claus, however, that their contents are composed of 

 coarsely granular protoplasm. That which appears such by low magni- 

 fication shows itself under high powers to be a beautiful network with 

 thickenings at the nodes of the meshes, which is brought out very plainly 

 by a cytoplasmic stain such as Lyons blue. Around the nucleus is seen 

 a more or less well-defined clear zone. What the function of the cell is 

 remains as unknown to me as to Claus and Schewiakoff. 



There is left one more point in reference to the nervous system upon 

 which I wish to say a word. Claus and Schewiakoff both describe the 

 wall of the crystalline sac as structureless, formed by the bare supporting 

 lamella. The credit is due to H. V. Wilson of finding in Chiropsalmus 

 that it has a special lining of epithelial cells, which he figures as a con- 

 tinuous, flattened layer. In both Charybdea and Tripedalia I find traces 

 of the same in nuclei here and there, but whether they are the remains 

 of a once continuous layer or not the sections do not show satisfactorily. 



This ends the account of what it seemed worth while to say at 

 present upon the nervous system. In concluding, the writer wishes to 

 express his thanks for the help afforded by Dr. Wilson's notes, in par- 

 ticular on the subject of the vascular lamellae, and desires to make 

 especial acknowledgment of his indebtedness to Professor Brooks, whose 

 suggestions, based upon many years of experience with the Medusa?, 

 have been most welcome and helpful, and whose evidences of unfailing 

 kindliness, both in Jamaica at the time the material was obtained and in 

 Baltimore when it was being studied in the laboratory, take a most 

 honored part in the pleasant memories associated with the work. 



LITERATURE REFERRED TO. 



CLARKE, H. J. '78. Lucernarise and their Allies. Washington : Smithsonian 

 Institution. 



CLAUS, C. '78. Ueber Charybdea marsupialis. Arb. aus d. Zool. Inst. d. Univ. 

 Wien, Band II, Heft 2. 



DOFLEIN, F. '96. Die Eibildung bei Tubularia. Zeitsch. f. wiss. Zool., Bd. LXII, 

 Heft 1. 



HAECKEL, E. '79. Das System der Medusen. Jena. '81. Challenger Report on 

 the Deep-sea Medusae. Vol. IV. 

 8 



