OF THE INVERTEBRATE ANIMALS. 21 



Combustion. 

 a. 0-391 substance gave 0*656 carbonic acid and 0*229 water, 



^ rCarbon . . 46-74. 

 hence per cent.^jjyj^^gg^ 6-64. 



b. Astacus tnarinus. Claws. 

 Determination of the Ash. 

 0-4705 substance gave 0-008 ash = 1*7 per ceni. 



Nitrogen. 

 0-468 substance gave 0-479 ammonio-chloride of platinum 

 = 6-54 per cent, nitrogen. 



Combustion. 



a. 0-842 substance gave 1*409 carbonic acid and 0*479 water, 



, r Carbon . . .46-48. 

 hence per cent, ^jj^^^^g^^ ^ g.43^ 



b. 0-592 substance gave 0-994 carbonic acid and 0-342 water, 



, ^ r Carbon . . . 46-64. 



hence per cent. -j^jjy^^^gg^ 6-53. 



c. Squilla mantis. Tegument, claws and pairs of feet. 

 Determination of the Ash. 

 0-2007 substance gave 0-0012 ash = 0*6 per cent. 



Nitrogen. 

 0*320 substance gave 0*344 ammonio-chloride of platinum 

 = 6*79 per cent, nitrogen. 



Combustion. 

 0-3795 substance gave 0-643 carbonic acid and 0*230 water, 

 ^ r Carbon . . . 46*54. 

 hence per cent. ^Hydrogen . 6*77- 



Or:— 



Astacus fluviatilis. Astacus marinus. Squilla mantis. 



\.a. 2. l.a. h. 1. a. 



Carbon . . . 46*74 . . . 46-48 46*64 46-54 



Hydrogen . 6-64 . . . 6-43 6-53 6-77 



Nitrogen . 6-59 6-35 6-54 . . . 6*79 



The shield of these animals however still contains a certain 

 quantity of lime-salts, viz. carbonate and phosphate of lime with 

 a little phosphate of magnesia. The proportions by weight of 

 the latter to one another, as also to the surrounding chitine- 



