DoNALDSON-ScHOEMAKER, Neviwiis System of Fi'ogs. 123 



The weight of the tissues surrounding the bones and cov- 

 ered by the skin — that is, the muscles, tendons, nerves and ves- 

 sels — is that recorded as the weight of the muscles. The rec- 

 ords for the left leg always stand first in the table. 



Length of leg bones. — The bones were measured with a 

 caliper square reading to o. 2 mm. In the case of the foot, 

 the length was taken from the proximal end of the apophy- 

 sis of the calcaneum to the tip of the fourth toe. 



Weight of the brain. — The brain, within the limits given 

 below, was raised on a narrow spatula, and the cranial nerves 

 cut at their junction with it. The pia was for the most part 

 left adherent. The choroid covering, the fossa rhomboidalis, 

 and the hypophysis, were both removed, however, before the 

 weight was taken. 



Weight of the spinal cord. — The roots of all the spinal 

 nerves were cut close to the cord itself, and this, still covered 

 with the pia, was then weighed. 



Length of the brain. — With spring compasses the measure- 

 ment was made from the frontal end of the olfactory lobes to 

 the caudal end of the calamus. The olfactory bulbs and tracts 

 were thus excluded. 



Length of the spinal cord. — The cord was measured in the 

 same manner as the brain. The limits chosen were from the 

 tip of the calamus to the point of attachment of the dorsal 

 roots of the tenth spinal nerve. ^ 



The plane separating the brain from the cord thus fell a 

 small fraction of a millimeter cephalad to the point of emerg- 

 ence of the first spinal nerve. 



X. Growth. 



The smallest specimens of R. virescens brachycephala 

 which we obtained early in the spring, weighed about 3.4 grms. — 



* The spinal nerves are designated according to the older enumeration I-X, 

 and not the more recent numbering II-XI, as advocated by Gaupp in his 

 edition of A. Ecker's und R. Wiedersheim's Anatomic des Froches. Lehre 

 von Nervensystem. 1897, S- 3- 



