276 



ZOOLOGY 



SECT. 



straighten, one part upon another; adductors which draw towards, 

 and abductors which draw away from, the middle line ; elevators 

 which raise, and depressors which lower, a part, such as the lower 

 jaw. The names of the muscles may have reference to their 

 position, e.ff. pcctoralis (pet.), the principal muscle of the chest ; or to 

 their form, e.g. biceps, the two-headed muscle ; or to their action, 

 e.g. flexor tarsi ; or to their origin and insertion, e.g. coraco- 

 humeraUs. 



Digestive Organs. — The mouth leads into a wide buccal cavity 

 having in its roof the interned or posterior nares (Fig. 929, p. na.), 



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Fig. 929. — Rana temporaria. Dissection from the left side ; the viscera somewhat displaced. 

 an. anus ; h. d. bile-duct ; 6. hy. body of hyoid ; hi. uruiary bladder ; bl.' its opening into the 

 cloaca ; c, art. conus arteriosus ; chlm. cerebellum ; cl. cloaca ; en. 3, centrum of third vertebra ; 

 cp. ad. corpus adiposum ; crb. h. cerebral hemisphere ; d. ly. s. dorsal Ij'mph sinus ; du. duo- 

 denum ; ep.cor. epicoracoid ; eus. t. Eustachian tube ; 'FR. PA. fronto-parictal ; gl. glottis ; 

 gul. gullet ; il. ilium ; is. ischium ; kd. kidney ; I. au. left auricle ; I. Ing, left lung ; Ir. liver ; 

 M. Mt'K. mento-meckeliau ; n. a. ly neural arch of first vertebra ;. olf, I. olfactory bulb ; opt. I. 

 optic lobe ; o. st. omostemum ; pcd. pericardium ; PMX. premaxilla ; 2>'>^- pancreas ; 

 p. na. posterior naris ; j9K. pubis ; ret. rectum ; )■. Ing. right lung ; s. int. small intestine ; 

 s/x cd. spinal cord; spu.etji. sphenethmoid ; spt. spleen; st. stomach; s. v. sinus venosus ; 

 tng. tongue ; is. testis ; ur. ureter ; ur'. its aperture into the cloaca ; ust. urostyle ; v. ven- 

 tricle ; V. ly. s. ventral lymph sinus ; vo, t. vomerine teeth ; vs. sem. vesicula seminalis. 



a pair of projections due to tbe downward bulging of the large 

 eyes, and the openings of the Uicstachian tubes (etcs. t.j vide infra). 

 On its floor is the large tongue (tng.), attached in front and free 

 behind, where it ends in a double point ; by means of its muscles 

 it can be suddenly projected, point foremost, from the mouth, and 

 is used in the capture of Insects. Immediately behind the tongue 

 is the glottis {gl.). Teeth are arranged in a single series round the 

 edge of the upper jaw, attached to the premaxillse and maxillae; 

 there is also a small patch of teeth (vo. t.) on each vomer just 

 internal to the posterior nostril. The teeth are small conical 

 bodies, their bases ankylosed to the bones; their only use is to 

 prevent the polished or slimy bodies of the prey — Insects and 

 Worms — from slipping out of the mouth. 



