157 



Another remarkable feature in the development of Dactylethra is 

 that of the position of the fore limbs ; these in common Batrachians 

 are formed in the respiratory sacs just exteriorly to the gills ; the left 

 leg protruding outwards by the respiratory orifice, and the right by a 

 corresponding opening on the right side, formed by the absorption of 

 the skin for the purpose of freeing the limb. In Dactylethra the fore 

 limbs are formed in special sacs, which are situated some distance 

 behind the organs of respiration. 



The urinary bladder is already somewhat developed, is formed 

 relatively much earher than in ordinary Batrachians, and in this 

 respect more closely resembles a true allantois. 



While in many respects the genus Dactylethra resembles Pipa, as 

 in the conformation of the limbs, the single Eustachian tube, the 

 absence of a tongue, and the broad transverse process of the coccyx, 

 it differs widely from it in its phases of development, especially in 

 the mode of the formation of the limbs and the position of them in 

 the embryo. 



Prof. J. Wyman gave an account of some experiments 

 recently made by him on Planarige, showing their jDOwer of 

 repairing injuries. 



One experiment consisted in cutting longitudinally the hinder half 

 of one side of a Planaria. The incision began on the side, extend- 

 ing to the middle hne, and then lengthwise, backwards to near the 

 end of the body, so that the severed portion hung by a slender neck, 

 and trailed backwards. At the end of the first day the separated 

 portion was restored to its natural position, and by the third day was 

 wholly united with the rest, the only indication of the injury being a 

 small notch on the side. 



In a second experiment the body was divided lengthwise from be- 

 hind forwards for about two-thirds of the length of the animal. The 

 divided portions completely cicatrized, but did not unite with each 

 other, so that the Planaria remained permanently bifid behind. 



In a third experiment the Planaria was divided in the middle 

 transversely. The fore part continued to move as usual, but the 

 hinder remained stationary. In the course of a few days the fore part 

 reproduced what it had lost, and the hinder reproduced the head and 

 eye specks, and thus two perfect animals were formed, both moving 

 with perfect freedom. 



Professor Carlo Matteucci, of Turin, was elected an Hono- 

 rary Member. 



