398 Dr. O. Rosenheim. Chitin in the Carapace of [May 27, 
luteum is formed and this organ provides a further secretion whose function 
is essential for the changes taking place during the attachment and 
development of the embryo in the first stages of preenancy. 
Chitin in the Carapace of Pterygotus osiliensis, from the Silurian 
Rocks of Oesel. 
By Otro RosENHEI™, Ph.D. 
(Communicated by Professor W. D. Halliburton, F.R.S. From the Physiological 
Laboratory, King’s College, London. Received May 27,—Read June 8, 1905.) 
Professor E. Ray Lankester, who has been interested in the constitution of 
the carapace of certain fossil Eurypterids found in Oesel in rocks of Silurian 
age, placed the matter in the hands of Mr. Bather, of the Geological 
Department, Natural History Museum. 
In March last Mr. Bather asked Professor Halliburton’s co-operation in 
the chemical investigation, stating that a preliminary examination, made by 
himself and Mr. G. T. Prior, led them to believe that the material retained its 
chitinous nature. When the small fragments of the carapace, which were all 
that could be spared from the duplicate specimens in the British Museum, 
arrived in this laboratory, Professor Halliburton placed them in my hands, 
and I proceeded to examine them for chitin. 
Gamgee, in his ‘ Text-book of Physiological Chemistry,* gives a long list 
of various invertebrate structures, mainly epiblastic, where chitin has been 
described, but the list is only approximately accurate, as Gamgee points out 
that, in many cases, a chitinous composition has been ascribed to a structure 
solely on the ground of its insolubility in caustic alkalis and dilute acids, or 
even in only one of these two classes of reagents. In 1884 the list was 
extended by Halliburton,t who showed that the cartilages occurring in 
Sepia and Limulus contain a small percentage of chitin; this was confirmed 
in the case of Sepia by Krukenberg,t who found the same material in the 
skeletal structures in that animal. It has further been found in certain 
fungi.§ 
* Vol. 1, p. 299. 
t ‘Roy. Soc. Proc.,’ No. 235, 1885; ‘Quart. Journ. of Micros. Science,’ vol. 25, p. 173 
1885. 
t ‘Ber. d. deutsch. Chem. Ges.,’ vol. 18, p. 993, 1885. 
S Gilson, ‘Comptes Rendus,’ vol. 120; Winterstein, ‘Ber. d. deutsch. Chem. Ges.,’ 
vols. 27 and 28. 
