312 JAMES EDWAED ACKERT 



the elongated ridges containing the largest blood vessels and 

 much connective tissue. 



2. A double meduUated nerve layer in the deeper part of the 

 corium, extending throughout the membranes. 



3. A layer, likewise double, present in the entire Malpighian 

 stratum, and consisting of numerous branches of non-medul- 

 lated nerve fibrils. 



A comparison of the foregoing results shows that the first 

 nerve layers of Schobl and of the writer coincide; that Sabussow's 

 first layer included Schobl's first and second layers and the 

 writer's first, together with the innermost branches of his second 

 nerve layer. A study of sections from different parts of the 

 membranes has convinced the writer that Schobl's second, third 

 and fourth nerve layers may well be considered as one layer, the 

 writer's second. Close to the body, where these membranes 

 are thick, and where Schobl probably made his observations, 

 since he especially recommended this region for study, it is true 

 that the writer's second layer is thicker dorso-ventrally than it is 

 near the elbow, or in the region midway between the body and 

 the tail. But at the periphery, between the elongated phalanges, 

 and near the posterior border of the interfemoral membrane, 

 where the skin duplicature is thin, this nerve layer is exceedingly 

 compressed. The contention of Sabussow that Schobl's second 

 nerve layer lay in the same plane as the first, and consequently 

 could not be considered as a separate layer, is not supported 

 by the present observations. Schobl's first layer is to be found 

 in the stratum reticulare, while the second, arising by repeated 

 dichotomous branching of the first, takes a position in the deeper 

 part of the superficial layer of the corium. The writer's second 

 nerve layer corresponds to Schobl's second, third and fourth 

 layers, while Sabussow's second layer includes the third and fourth 

 layers of Schobl, and the greater part of the writer's second. The 

 third nerve layer of Sabussow and of the writer, respectively, 

 corresponds to Schobl's fifth. 



