AJSTATOMT OF THE COMMON FROG. 475 



in front is tlie tibialis anticus (ta). On the dorsal surface 

 of the thigh (Pig. 433, III) the glutceiis {gl), the pyriformis 

 (p), the rectus anticus femorus (ra), the vastus externus 

 {ve), the biceps (b), the semimembranosus {sm), Ij'ing deep 

 between the biceps and semimembranosus are seen the 

 femoral vessels and sciatic nerye ; the rectus anticus, vastus 

 internus and externus are known collectively as the triceps 

 femoris ; in the leg the gastrocnemius (g) iindperoncBus (p). 



The sympathetic nerves can be seen as two cords, one on 

 either side of the vertebral column. The spinal nerves can 

 be seen as white threads on the dorsal surface of the body- 

 cavity. The brain may be dissected out by opening the 

 skull from above ; its parts and its connection ^nth the 

 spinal cord are sufBciently illustrated by reference to Pig. 

 368. The seventh, eighth, and ninth spinal nerves unite to 

 form the very large sciatic trunk ; the intercommunications 

 of these nerves form the lumbar plexus ; while the second 

 and third spinal nerves form the brachial plexus from which 

 arises the brachial nerve. (0. S. Minot.) 



Certain glands in the skin of some Batrachians secrete a 

 corrosive, or as in the European Salamandra, maculosa, a nar- 

 cotic poison, which is poisonous to small animals. The 

 toads secrete in the parotid glands a bad-smelling fluid, 

 which applied to tender skins produces erysipelas. Lacerda 

 states that the poison of the Brazilian B^ifo ictericus is a 

 milky humor from the glands on the sides of the neck. The 

 action of the poison is less fatal to small animals than that 

 of the European toad ; it gives a slight acid reaction and is 

 not soluble in alcohol, while that of the European toad is. 



Like fishes, the Batrachians assume high colors during 

 the breeding season. The males of the newts at this time 



Fig 433 —Anatomy of common Frog. My, mylohyoid ; «)•, sternoradials ; th, 

 thyroid- 111. lungs; f, fat-body; Te, testis; St, stomach; Sp, spleen; R, rectum; 

 (J adductor lon^us'; mvl, vastus internus; »w, sartorms; ?■»', rectus internus 

 niaior • la tibialis anticus ; (j, gastrocnemius ; rl", rectus internus minor ; a", ad- 

 ductor' magnus ; rab, rectus' abdominalis ; B, bladder ; vd, vas deferens ; S, gall- 

 bladder; Kl, kidney ; pv, portal vein ; Li, liver ; T, vena cava inferior ; Ao, aorta ; 

 ,?, vocaVsac.'or croaking-bag. . .■ , , , v k ■ 



II Origin of the arterial trunlcs, I, arteria mgualis ; eg, carotid gland, which is 

 mere'lv a rete tnireMle ; cr, carotid artery ; Ao, aortic arch ; Pa, pulmonary artery. 



in Dorsal view of muscles of hind leg. gl, gliitffiiis ; ra, rectus aiiteiior ; /;, pyri- 

 formis • ve, vastus externus ; sm, semi-membranosus ; b, biceps ; g, gaatrocuemuis ; 

 per, peronieus.— Drawn by C. S. Minot. 



