CHAP, xi TEETH 509 



ofEustachian tube;/;/. Fallopian tube; g. b. gall-bladder; //./. hard palate; 

 h. p' . bones of hard palate ; hy. hyoid ; i. incisors ; il. ileum ; i. n. passage of 

 internal nostrils ; j. Jacobson's organ ; k. left kidney ; /. au. left auricle ; Ing. 

 left lung, seen through pleura ; Ir. liver ; lv. 4 . fourth lumbar vertebra ; /. vn. 

 left ventricle ; m. tb. maxillary turbinal ; n. p. c. naso-palatine canal ; n. ph. 

 naso-pharynx ; n. tb. naso-turbinal ; n. s. nasal septum (middle part cut away) ; 

 as. gullet ; o 1. I. olfactory lobe ; ov. left ovary ; /. a. pulmonary artery ; pc. 

 pericardium ; per. gl. perineal gland ; ph. pharynx ; phr. n. phrenic nerve 

 (origin not shown) ; /. m. a. posterior mesenteric artery ; p. mx. premaxilla ; 

 pn. pancreas ; pn. d. pancreatic duct ; pr. c. left precaval ; p. sy. pelvic sym- 

 physis ; pt. c. postcaval ; py. st. pyloric region of stomach ; r. ribs ; ret. rectum ; 

 r.gl. rectal gland ; r. vn. right ventricle ; sk. f. floor, and sk. r. roof of skull ; 

 si. gl. sublingual gland ; s. mx.gl. submaxillary gland ; s.p. soft palate, ending 

 in the] velum palati, on the lower side of which a tonsil is seen ; sp. c. spinal cord ; 

 sp. n. spinal (lumbar) nerves ; s. r. sacculus rotundus of ileum ; s. v. first sacral 

 vertebra ; sy. sympathetic (the anterior end shown on the right side, the rest on 

 the left) ; t. tongue; thr. thyroid ; th. v. Q ninth thoracic vertebra ; thy. thymus ; 

 tr. trachea ; u. bl. urinary bladder ; ur. ureter ; ut. uterus ; vag. vagina ; vb. 

 vestibule ; Tjg. vagus (the anterior end shown on the right side, the rest on the 

 left) ; vul. vulva. 



outer margin. The tongue (/) lies on the floor of the mouth 

 to which it is attached below, its anterior, rounded end 

 being free : the surface of its posterior part is elevated, and 

 elsewhere but more particularly on the tip its covering 

 of mucous membrane is produced into minute, finger- 

 shaped papilla, on which some of the microscopic organs 

 of taste are situated (compare p. 180). Taste-organs are also 

 present on a pair of circumvallate papilla on the dorsal side 

 of the tongue towards its posterior end, and on a pair of 

 transversely ridged areas the foliate papillae, situated 

 laterally, slightly anterior to the former. The main 

 substance of the tongue is composed of muscles, some 

 extrinsic, or arising from other parts, and others in- 

 trinsic, or entirely confined to the organ in question. 



The teeth (Figs. 132 and 133), as we have seen, are not all 

 alike, as in the dogfish and frog : there are incisors and cheek- 

 teeth or grinders, the latter being divisible into two series 

 the premolars and the molars. In most Mammals there is 

 also a pair of canine teeth, situated between the incisors and 

 premolars, and these are especially long and pointed in such 

 carnivorous animals as the dog and cat. In the dogfish 

 and frog, again, the teeth are continually renewed as 



