8 Introduction to Animal Morphology. 



tissues, Calcium Carbonate either in a crystalline or 

 nodular form, usually the latter, in forms similar to 

 those assumed by it in deposits from viscid solutions 

 (see Hurting, Verhandelingen der Koninklijke Akad., 

 Amsterdam, 1873, 13 Deel, p. 4), Nitrogen in the 

 swim-bladder of fishes, &c.. Hydrochloric acid in 

 the gastric juice. Sulphuric acid in the. saliva of 

 Dolium galea, &c. 



dilute acids, gelatinizing on cooling, precipitable by alcohol, corrosive 

 sublimate, &c. 



Chondrin, formed by boiling chondrogen, which forms the hyaUne 

 basis of cartilage, C16H26N2O7 precipitable by acetate of lead, alum, but not 

 by mercuric chloride. 



Ossein from the intercellular substance of bone resembles Gelatin in 

 niost of its properties, but is more soluble. 



Elastin from yellow elastic tissue is insoluble in water, alkalies, and 

 most reagents, except strong solution of Potass. 



Spongiolin, aUied to Keratin, is the element making the homy skeleton 

 of sponges. 



Conchiolin, allied to Gelatin, is the animal element in the shells of 

 Mollusca. 



Acanthin, like Spongiohn, is the substance which composes the spicules 

 in some Radiolaria. 



Neossin, like Gelatin, is the element of which the Edible Birds' nests 

 are made. 



Chitin, the indurating material of the integument of Arthropods, 

 CizHjgNjOn insoluble in all ordinary reagents, except in strong mineral 

 acids. 



The non-nitrogenous elements are fats, which consist of the following : — 



(O.C18H35O 



Stearin C3H"'5 O.CHssO 



( O.C1BH35O 



(O.CisHaiO 



OleinCsH'-'s { O.C18H33O 



(O.CsHsaO 



( O.C16H31O 



Palmitin C3H"'6 { O.CieHsiO 



I O.CieHaiO 



_.v J • J r 1 * r> -LT'* I rMLT by the substitution of acid 



These are denved from glycennC^H 5 j OH ^radicles for hydrogen. ' 



