1903.] AXATOMY OF THE JAPANESE SALAMANDER. 307 



perfoi'm their function perfectly. On the other hand, this could 

 hardly be the case with the big Salamander ; and it may be that 

 the unequal growth of the various parts of the heart is a direct 

 cause of death*. 



Concerning the second row of valves I have nothing to add to 

 the account given by Osawa, who corrects previous errors t. 



Synangium. — A transverse section through the synangium at 

 about its middle point shows that the term " synangium " is 

 especially applicable to Megalohatrachus. In Menohranchus this 

 region of the heart as figured by Huxley { is divided into four 

 cavities only, the subsequent subdivisions of which form the several 

 aortic trunks. In Megalohatrachus all the arteries may be said to 

 arise separately from the pylangium. The transverse section, in fact, 

 shows the cavity of the bulky synangium to be primarily divisible 

 into a right and left half. Each half is again divided by septa into 

 cavities, which are those of the four arterial trunks. These are 

 placed one above the other in a seiies of stories, and increase in 

 size from below upwards, the lowest and smallest being, of course, 

 the Carotid and the largest and most dorsal the Pulmonary. The 

 vertically-disposed origin of the arteries contrasts with their 

 nearly horizontal position on emergence from the common 

 sheath §. 



§ Aortic Arches. 



I do not find that my dissections of the arteries arising from the 

 conus arteriosus agree altogether with the figures or the descrip- 

 tions of Hyrtl and Osawa, even in important details. As will be 

 seen from the drawing submitted herewith (text-fig. 33, p. 311), 

 there are four branches, as is correctly shown by Schmidt, 

 Goddard, and Van der Hoeven in their memoii- |i, and by 

 Dr. Chapman % and Prof. Osawa **. ISTor are the views which 

 Hyrtl gives of sections through the conus arteriosus correct ac- 

 cording to my own observations. When the conus is cut through 

 just before the arteries diverge, the four trunks are seen to 

 lie close together in the relations shown in the accompanying 

 drawing (text-fig. 31, p. 308). The largest cavity is that of the 

 pulmonary trunk ; the two next largest are subequal and belong 

 respectively to the two aortic trunks. The smallest is that of the 

 carotid. I need say nothing of the exact position which each 

 holds in the complex, inasmuch as the facts are accurately shown 

 in that drawing. If the drawing be compared with the two 

 figures given by Hyrtl and with those of Osawa which illustrate 



* See note in ' Nature,' vol. Ixviii. p. 497 (1903). 

 f Loc. cit. 



t Loc. cit. pi. xxxii. fig. 6 a. 



§ It will be seen that my drawing does not agree with that of Osawa {loc. cit. 

 pi. xxxviii., B and C). 



II " Aanteekeningen over de Anatomic van den Cryp^oSrawc^MS yopowicMS," Nat. 

 Verh. Maatsch. Wetensch. Haarlem, deel 19, 1864. It is curious that this error 

 should have been perpetuated in Bronn's ' Thierreich ' by the reproduction of Hyrtl's 

 figures. 



1 Proc. Acad. Nat. Sci. Philad. 1893, p. 227. 

 ** Loc. cit. pi. xii. figs. 1 & 4. 



20* 



