1903. j AXATOMY OF THE JAPANESE SALAMAXDEU. 301 



however, the oviducal mesentery leaves the coinmon dorsal 

 inesenteiy, and goes to the light and to the left to follow the 

 oviduct to its internal apertui-e. The aorta itself is lemoved by 

 quite a long distance from the dorsal median line, from which the 

 dorsal mesentery, over an inch wide in parts, suspends it. It 

 should be observed that this membrane is continuous and not 

 fenestrated as it is in the fi'og, where the aorta also does not lie 

 close to the backbone. Within this mesentery are suspended the 

 intercostal arteiies and certain portal veins, both of which are de- 

 scribed elsewhere (see p. 312). The halves of this mesentery are 

 so loosely attached to each other that the slightest pull brings 

 them apart. I am disposed to think that this ready separation 

 argues a lymph-space or spaces of considerable extent within the 

 cavity of this dorsal mesentery. 



The above description of the mesenteries has been given partly 

 to serve for a comparison with Alenopoma. The differences 

 between the two forms are not, however, great. In the first place, 

 the left lung is very much shoi-ter than the right in Menopoma. 

 In Jlegalobatrachus it is slightly longer. Nevertheless, in Meno- 

 jjoma the free tip of the lung to which no mesenteiy is attached 

 is proportionately much longer than in 3fegalobatrachus . Finally, 

 the left lung of Ifenopoma is connected only with the oesophagus. 

 This membrane, however, runs for a little distance over the 

 mesentery attaching the stomach to the aorta, and is a trace of 

 the former greater extension of the lung. The gastro-hepatic 

 ligament bears, of course, the gastric and oesophageal branches of 

 the portal, which show differences in the two animals. In both, 

 the oesophageal portal is quite distinct fi-om the gastric, and enters 

 the liver at about the middle of its length. Ln Ahnopoma this 

 trunk is formed by the union of two equally sized vessels. In 

 Megalohatrachus there is but one. In the larger specimen of this 

 genus, moreover, the condition was still more specialised ; there 

 was no separate oesophageal trunk at all, Furthermoi-e, in 

 Menopoma the gastric trunk consisted of two main trunks meeting 

 near to their entrance into the liver posteriorly ; the anteiior of 

 these has two branches, the posterior three. In Megalohatrachus 

 this vessel is more obviously one trunk with many branches. 

 These and other reasons (such as the at least general persistence 

 of a pair of gill-slits) lead me to dissent from those who would 

 unite the American and Japanese Salamanders into one genus, 

 Cryjitobranchiis. 



A sheet of membrane, quite tough in character, extends from 

 the right lobe of the liver to the parietes, and arches over a section 

 of the body-cavity. Into the pocket formed at the corner of this 

 next to the lateral parietes opens the oviduct. The general 

 relations of these various parts are shown in the accompanying 

 sketch (text-fig. 28). This cavity is entii-ely floored by the lung, 

 and its boundary near the middle line of the body is the 

 mesentery connecting the liver with the lung. On the right side, 

 and below the shelter afforded by the transverse and horizontal 



