184 BULLETIN OF THE BUSSEY INSTITUTION. 
In conchiolin, obtained from the horny axis of a gorgonia coral, Fremy * 
found 16.8%, of nitrogen, and in conchiolin from sea-shells, 17.5%. 
There is one item in the table which is truly remarkable, and that is 
the large proportion of nitrogen f in the shell of the horseshoe or king- 
crab, —a result which is almost as eccentric and extraordinary as the 
king-crab itself is among crustaceans. 
It would be interesting to study this nitrogenous matter, with the 
view of determining wherein it may differ from the chitin that is found 
in the shells of the Jobster and crab, and whether or not it is allied to 
the ossein of bone or the conchiolin of sea-shells. But I am at present 
unable to undertake this inquiry. In this connection, it is noteworthy 
that C. Schmidt,t on examining the leathery or membranous outer 
covering of an ascidian mollusk ( Cynthia mammillaris), which consisted 
almost entirely of water, and contained no more than 1.07% of dry 
* “ Annales de Chimie et de Physique,” 1855, 43. 97. Silliman (Liebig and 
Kopp’s ‘‘ Jahresbericht der Chemie,” 1850, 3. 813) found about 6 % of ashes in 
the horny stem of Gorgonia antipathes from Bermuda. 
+ In order to be perfectly sure upon this point, and for the sake of deter- 
mining whether any one part of the shell of the king-crab contains a larger pro- 
portion of nitrogen than the other portions, I have had made several new 
estimations of the amount of nitrogen in different parts of the shell of one 
large individual king-crab, as follows: It will be remembered that the figures 
given in the large table relate to a mixture of material that was obtained by 
powdering the shells of several crabs of different sizes. It is to be observed, 
moreover, that the results recorded in this note were obtained by another ana- 
lyst, who had had nothing to do with the work given in the large table. 
A. Ina sample of shell taken from the centre of the anterior section of the 
upper covering of a large king-crab, and dried at 108° to 110°, there was found 
10.94 %, and 10.96 % of nitrogen, in two separate trials. ‘Since the air-dried shell 
lost 9.75 % of moisture in the process of further drying, the above figures corre- 
spond to 9.87 % and 9.89 % of nitrogen in the air-dried shell. 
B. Shell from the posterior section of the old king-erab, dried at 108° to 
110°, gave 13.65% and 13.87% of nitrogen. The air-dried shell lost 8.46 % of 
moisture when dried as above stated. 
C. Shell from the posterior section of a young king-crab, dried at 108° to 
110°, gave 18.35 % of nitrogen; and the air-dried shell lost 11.10% of moisture in 
the process of drying. The air-dried shell contained 11.87 % of nitrogen. 
D. Air-dried shells of the legs of the old king-crab lost 6.86 % of moisture on 
being dried at 108° to 110°. There was found 11.09 %, 11.50%, and 12.14% of 
nitrogen in the thoroughly-dried shells, or 10.33%, 10.71%, and 11.81% in the 
air-dried shell. 
The mean of all these estimations, equal 12.18 % of nitrogen in mixed shell of 
the king-crab dried at 108° to 110°, differs but little from the numbers given in 
the large table. 
¢ ‘‘ Annalen der Chemie und Pharmacie,” 1845, 54. 818. 
