354 



Mr. A. Sedgwick. 



[May 21, 



V. " The Development of Peripatus Capensis." By Adam 

 Sedgwick, M.A., Fellow of Trinity College, Cambridge. 

 Communicated by Professor M. Foster, Sec. R.S. Received 

 May 9, 1885. 



The development of Peripatus capensis was first studied by 

 Moseley, who stopped for a short time at the Cape in November and 

 December some years ago. His observations related only to a 

 few stages comparatively late in development. Balfour, in 1882, 

 found some younger embryos in specimens collected by Mr. Lloyd 

 Morgan in July and August. He had only time to make a very few 

 observations, of which he left a short record in the form of four rough 

 drawings and a short note, and a letter to Prof. Kleinenberg, before 

 starting on his last expedition to Switzerland. His observations 

 were so interesting that they were made the subject of a short com- 

 munication to the Royal Society in the autumn of 1882, and they 

 were slightly extended by the editors of his last work on the anatomy 

 of Peripatus capensis, and published with that monograph in the 

 u Quarterly Journal of Microscopical Science " in the spring of 1883. 



The subject seemed so important that the Government Grant Com- 

 mittee of the Royal Society granted, in the spring of 1883, the sum 

 of £100 to enable me to go to the Cape for the purpose of obtaining 

 well-preserved embryos, and of studying the development on fresh 

 specimens. 



Accordingly, I went to the Cape in the summer of 1883, arriving 

 early in July, and remaining till the middle of August. I obtained a 

 large number of specimens, and brought back with me over 300 alive. 

 Some of the latter lived at Cambridge till the following July. The 

 results of my observations at the Cape and after my return to England 

 have been to show that the embryos remain thirteen months in the 

 uterus ; that the fertilised ova pass into the uterus in April, and the 

 young are born, fully developed, in the May of the year following. 

 That is to say, the young ova pass into the uterus one month before last 

 year's young are born. I was not prepared for this, and I did not, in 

 1884, examine my specimens for the early stages until May, when the 

 young were being born. The result was that I missed last year the 

 early stages of development, and had it not been for the kindness of 

 Mr. Walter Heape, who went to South Africa last summer, and who 

 collected and brought back some more live specimens, I should have 

 been obliged to leave the early stages undescribed. Thanks to him, 

 however, and to my experience gained last year, I have this April 

 been able to find several of the younger stages, and to complete my 

 •observations. 



The testes are fully developed and charged with ripe spermatozoa 



