324 BRUNER. [Vol. XVI. 



ment of valves in the heart, and pointed out for the first time 

 the function of the spiral valve in regulating the direction of the 

 flow of blood, 



Langerhans (21) described the perforations in the septum 

 atriorum of Urodela. His results were later confirmed by 

 Huxley (15) and Boas (6). 



Boas (5) investigated the spiral fold of the salamanders, and 

 showed it to be formed by the fusion of a row of valves. Indi- 

 cations of this origin are still to be found in some forms (Triton 

 cristatus), in which the valve is represented by a row of knots 

 on the conus wall, 



Gompertz (12) published an excellent account of the physi- 

 ology of the anuran heart in 1884. 



Langer (19) worked out the development of the proximal 

 and distal valves of the conus arteriosus. Thickenings repre- 

 senting these valves appear in a very early stage of the larval 

 development. Later these thickenings are hollowed out next 

 to the conus wall. 



The literature of the lungless salamanders begins in 1894, 

 when Wilder (35) announced the discovery of a number of 

 species. The same year Camerano (9) discovered two lungless 

 Italian forms. In 1896 Wilder (36) and Lonnberg (22) each 

 added a number of species to the list, which, according to 

 Wilder, includes at least half of the known species of Sala- 

 mandrinae. 



Camerano (9) attempted to determine the mode of respira- 

 tion of Salamandrina perspicillata and Spelerpes fuscus, follow- 

 ing the method of Marcacci (37) with the frog, by hindering the 

 bucco-pharyngeal respiration. As the animals experimented 

 with quickly died, in spite of the fact that the cutaneous res- 

 piration was undisturbed, Camerano concluded that the latter 

 is relatively unimportant in sustaining life, while the bucco- 

 pharyngeal respiration is really essential thereto. 



Bruner (2) found special muscles for opening and closing 

 the external nares in the lungless salamanders. In salaman- 

 ders with lungs these muscles constitute an important part of 

 the mechanism of inspiration. In lungless forms, however, 

 their function seems to be restricted to the protection of the 



