XII 



PHYLUM CMORDATA 



417 



well-developed digits, and on the tibial side of the first is a 

 spur-like structure or calcar (C), formed of three bones, a 

 metatarsal and two phalanges : such a rudimentary digit is 

 called a pre-hallux. 



The mouth leads into a wide buccal cavity having in its 

 roof the posterior nares (Fig. 25 i,/. ), a pair of projec- 

 tions due to the downward bulging of the large eyes, and the 



olfl 



/MX 



vo.l 



FIG 251. Rana temporaria. Dissection from the left side; the viscera somewhat 

 displaced, an, anus; b. d, bile duct; b. hy, body of hyoid; bl, urinary bladder; 

 bl' , its opening into cloaca; c art, conus arteriosus; cblm, cerebellum; cl, 

 cloaca; en. 3, centrum of third vertebra; cp. ad, corpus adiposum; crb. h, cere- 

 bral hemisphere; d. ly. s, dorsal lymph sinus; du, duodenum; ep. cor, epicora- 

 coid: ens. t, Eustachian tube; FR. PA, fron to-parietal; gl, glottis; gnl, gullet; 

 IL, ilium; is, ischium; kd, kidney; I. an, lefc auricle; I Ing, left lung; lr, 

 liver; M. MCK, mento-meckelian; n. a. I, neural arch of first vertebra; olf.l, 

 olfactory lobe; opt I, optic lobe; o. ST, omo- and epi-sterntim; pcd, peri- 

 cardium; PMX, premaxilla; /;/, pancreas; / na, posterior naris; pii, pubis; 

 ret, rectum; r.lng, right hmg; s.int, small intestine; sp.cd, spinal cord; 

 SPH. ETH, sphenethmoid; spl, spleen; st, stomach; s. i>, s-inus venosus; tng t 

 tongue; ts, testis; ur, ureter; ur' , its aperture into the cloaca; UST, urostyle; 

 v, ventricle; T ly.s, ventral lymph sinus; i'o. t, vomerine teeth; vs. sent, 

 vesicula seminalis. 



Eustachian tubes (eus. /, 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 



2 E 



