1010 MR. L. R. CRAWSHAY ON THE ARTERIAL [Dec. 11, 



however, that in Bufo horeas a large dai-k reddish compact gland 

 attached ventrally to the distal end of the middle and posterior 

 arches, and similar in appearance to the thyroid, had no connection 

 whatever with this artery, but was snpplied on both sides of the 

 body by a branch of the subclavian*. 



From the point whei-e the r. lingualis passes backwards to 

 the tongue, a small bi-anch of the carotis externa is continued 

 forwards in the M. geniohyoideus to the edge of the lower jaw. 

 In R. tigrina and both species of Bufo this vessel ended here, but 

 in the rest of the species examined it foi'med an anastomosis with 

 the r. maxillaris ivferior of the A. occipitalis. 



A. carotis interna. — I was unable to observe the A. pliaryngea 

 ascendens desci-ibed and figured by Ecker, and afterwards in the 

 translation of Haslam, as a branch of this artery in a,ny of the 

 specimens examined, but in all cases the first subdivision of 

 the artery occurred just as it enters the inner posterior angle of 

 the orbit and passes into the skull, giving off" the Aa. ophthalmica 

 and joaZff^Mi!(X with other unimportant small vessels almost 

 sim-ultaneously. There is no reference to such a branch of the 

 carotid in Gaupp's edition, and unless its insertion can have been 

 due to some error, its occurrence as a notewoi'thy vessel would 

 seem to be abnormal. 



The connection of the A. palatina with the Harderian gland 

 was always very marked, the main vessel turning inwards to the 

 gland as it reached the anterior border of the orbit. This gland 

 occupied a constant position against the eyeball in close contact 

 with the M. ohliquus inferior. In R. hexadactyla it formed the 

 centre of a comijlete anastomosis between the Aa. palatina and 

 ojyhthalmica, and the orhito-nasalis and maxillaris superior of 

 the occipito-vertebralis, the palatina uniting with the orbito- 

 nasalis just before reaching the gland. The gland in this case 

 especially was completely sufiused with the colour of the injection, 

 as is so noticeable in the spleen, or, less distinctly, in the thyroid 

 (text-fig. 147, ^.A., ID. 1019). 



11. Systemic System. 



The A. laryngea was constant in occurrence and position, leaving 

 the systemic arch ojDposite to the carotid gland. 



As the systemic arch passes up to the dorsal body-wall, the first 

 trunk to be given off" was in all cases the occijnio-vertebralis, the 

 subclavia very soon afterwards branching off from the aorta 

 and crossing the base of the occijnto -vertebralis dorsally in its 

 outward course. 



The A. cesophagea seems in most cases to arise from the base of 

 the occipito-t^ertebralis . Such was the case in R. clavnata, R. hexa- 

 dactyla, R. tigrina, B. mauritanicus, and B. boreas. In R. tempo- 



* No attempt is made here to discriminate between tlie several factors wliicli may 

 make up the sometimes very irregular glandular masses in this region, and the terni 

 " thyroid " is used for them collectively with some reticence (cp. H. Norris, Anat. 

 Anz. vol. xxi. p. 221). 



