344 W. L. SCLATEK. 



of the genus Peripatus, will be able to clear up the diffi- 

 culties of the subject. 



It will be convenient, however, for me to distinguish the 

 species now under investigation from those treated of by 

 Kennel, and I propose, therefore, to allude to it as Peripatus 

 i m t h u r n i, since it was Mr. E. F. im Thurn who first discovered 

 Peripatus in British Guiana, and it was through his kindness 

 and hospitality that I was enabled to procure my specimens. 

 To Mr. Sedgwick also I owe very many thanks for all his 

 kindness and help to me in my work on this subject. When 

 I arrived in England it was he who preserved the specimens 

 and their embryos, and afterwards helped me with many 

 suggestions, besides allowing me to use all the many resources 

 of his laboratory at Cambridge for the prosecution of my 

 researches. 



II. Structure of the Uterus. 



When the uterus of Peripatus is examined it is found to 

 consist of a long and very much coiled duct, which commences 

 at the ovary as a slender tube, and, gradually widening, joins 

 its fellow to form a short vagina, and opens to the exterior at 

 the penultimate somite. 



The uterus in the lower part is divided up by constrictions, 

 the space between the constrictions being occupied by an 

 embryo. Advancing towards the ovary the constrictions are 

 longer and the swellings are smaller, till, for some distance 

 from the ovary, the swellings entirely disappear. These swell- 

 ings mark the position of the various embryos, and are usually 

 eight to ten in number. 



The position of the embryos is also marked by deposits of 

 pigment, which appear as a pinky-red colour when seen in the 

 solid uterus ; these patches are found not at the actual position 

 of the embryo itself but just in front and behind. In one or 

 two instances, in the case of a very young embryo (i.e. the one 

 nearest the ovary), the pigment was found to envelop it com- 

 pletely, so that it seems that the pigment is first formed all 



