1028 MR. L. 11. CRAWSHAY ON THE ARTERIAL [DeC. 11, 



eight ppecies under consideration a certain definite arrangement 

 traceable which would seem to form a safe basis of comparison : — 



Fii'stly, in all cases there was an A. circumflexa ilhtm, running 

 directly forwards sooner or later from the main trunk of the 

 femoralis, but the existence of two such ai'teries, arising inde- 

 pendently, and distinguished by Gaupp as intei^na and extei'na 

 respectively, I only found in E. esculenta. In all other cases, 

 the single vessel was to be identified with the A. circumflexa 

 ilium externa of that author. The A. circumfiexa ilium interna 

 was only represented by a branch or branches from this vessel, 

 running to the M. coccygeo-iliaciis ; and I do not think that this 

 artery will prove to have the value of an independent factor 

 of the A. femoralis of the Anura generally. Secondly, there 

 was in all the species an important biunch running backwards 

 and ventrally, chiefly to the muscles of the thigh. Thirdly, the 

 outward continuation of the artery, more especially to the skin 

 of the femoral region. The two latter branches I Avill refer to as 

 the A. muscidaris and the A. cutanea femor is lateralis respectively, 

 preserving so far as possible the nomenclature of Gaupp, though 

 the f oi'mer includes a number of arteries separately named by him 

 according to their division in the same region, while the latter 

 may, either partly or entirely, strike out into a region other than 

 that implied by its name. This arrangement of the branches of 

 the A. femoralis was shown more typically in R. esculenta, 

 R. temporat'ia, R. hexadactyla, R. clamata, and B. mauritanicus 

 (text-figs. 149, 150, 152). 



In Biifo mauritanicus, the circumflexa ilium interna was repre- 

 sented by a comparatively large branch of the A. circumflexa 

 ilium, running inwards to the M. coccygeo-iliacus, and backwards 

 to the cloaca ; and in this species there w^as an additional branch 

 from the base of the A. cutanea femoris lateralis to the m. iliacus 

 exter^ius. In R. tigrina the cutanea femoris lateralis was repre- 

 sented by an artery to the base of the M. rectus abdominis ; 

 while in B. boreas the same artery divided its supply between the 

 Mm. obliquus exteroius and obliquus interoius and the skin of the 

 trunk. In R. catesbiana there were two additional branches : the 

 first from between the circicmflexa ilium and the m.uscidaris, 

 running to the skin of the femoral region ; the second separating 

 from the cutanea femoris lateralis and supplying the Mm. rectus 

 anticus femoris and ilio-psoas, and also a recurrent branch (absent 

 on the left side) from the circumflexa ilium to the M. iliacits 

 internus. 



The circumflexa ilium originated proximally and before the 

 miiscularis in R. temporaria, R. clamata, R. catesbiana, B. boreas, 

 and B. mauritanicus, and either opposite or distal to it in R. hexa- 

 dactyla, R. tigrina, and R. esculenta. 



III. PULMO-CUTANEOUS SySTEM. 



A. cutanea magna. — The threefold division of this artery into 

 r. auricidaris, r. lateralis, and r. dorsalis occurred without much 



