ANIMAL ORGANIZATION. 87 



nation, they are found to be tied together by oblique fibres 

 curiously interlaced, in a way that no art can imitate. It is 

 only after long maceration in water, that this complicated 

 and beautiful structure can be unravelled. 



The mechanical properties of these fibrous structures, 

 which are strictly inextensible ligatures, render them appli- 

 cable to purposes of connexion where motion is to be re- 

 strained. Many cases, however, occur in which a substance, 

 is wanted, uniting great compactness and strength with a 

 considerable degree of elastic power. For this purpose a 

 different texture is fabricated, consisting of twisted fibres, 

 which impart this required elasticity. Such is the structure 

 of the elastic ligaments of animals, which are very gene- 

 rally employed for the support of heavy parts that require 

 being suspended. An instance occurs in quadrupeds, in that 

 strong ligament which passes along the back and neck to be 

 fixed to the head, and to support its weight when the ani- 

 mal stoops to graze. This, the ligamentum nitchde, as it is 

 termed, is capable of great extension, and by its elasticity 

 reacts with considerable force in recovering its natural length, 

 after it has been stretched. This ligament is particularly 

 strong in the Camel, whose neck is of great length.* Ano- 

 ther example of an elastic ligament occurs in that which con- 

 nects the two shells of bivalve mollusca (as those of the oy- 

 ster and muscle,) and which keeps them open when the ani- 

 mal exerts no force to close them. The claws of the Lion, 

 and other animals of the cat tribe, are retracted within their 

 sheaths by means of two strong elastic ligaments. Structures 



* Many birds are provided with strong- elastic lig-aments connecting- the 

 vertebrae of the neck with those of the back; ligaments of the same kind are 

 also employed for retaining the wing-s close to the body, where they are not 

 used in flying-: and a similar provision is made in the wing-s of bats. The 

 weight of the bulky org-ans of digestion in herbivorous quadrupeds require 

 some permanent support of this kind; and this is furnished by a broad, elas- 

 tic fibrous band extended across the lower part of the abdomen. It is par- 

 ticularly strong in the elephant, which remains more constantly in the liori- 

 zontal position than most quadrupeds: and it has been remarked that the g-e- 

 neral cellular texture in this animal has an unusual degree of elasticity. — 

 Hunter on the Blood, &c. p. 112. 



