INTERNAL ANATOMY OF INSECTS. 



no less than 2186; which, after deducting 20 that are 

 common to the gullet and the head, gives a total of 4061 a . 

 In the human subject only 529 have been counted b : so 

 that this minute animal has 3532 muscles more than the 

 Lord of the creation ! 



The muscles of the* Arachnida seem less numerous 

 than those of insects. In the Scorpionidea they appear 

 to be robust, formed of simple straight fibres, of a whitish 

 gray colour : a muscular web, rather strong, clothes the 

 parietes, but rarely adheres to them, of the abdomen, 

 and envelopes the viscera, with the exception of the lungs, 

 and probably of the heart. The dorsal part of this web 

 gives birth to seven pairs of filiform muscles, which tra- 

 verse the liver, and are attached to a muscular riband 

 which, passing above the lungs, runs the whole length 

 of the ventral parities. These muscles when exposed to 

 view resemble extended cords. The abdominal segment 

 preceding the tail is filled with a powerful muscular mass 

 which moves that organ . Treviranus discovered two 

 longitudinal muscles in Scorpio europceus, running from 

 the breast to the tail, which above and below each gill 

 were connected by another running transversely across 

 the heart, thus forming a quadrangular area in which 

 the gills are situate d . The heart appears to be moved 

 by muscles not very dissimilar to those of the Cossus e , 

 as is likewise that of the Araneidea ; in Clubiona atrox 

 the wider part of this organ is muscular, and incloses a 

 considerable cavity f . In this tribe the muscles of the 



Lyonet Anat. t. xiii. 188 ,584. b md. 189. 



c N.Dict. d'Hist. Nat. xxx. 421. d Arachnid. 9. t.'i.f. 7,r. 



* Ibid. o. ' Ibid. 10. 



