378 Labyrinthici and Holconoti 



"The female genital apparatus in the state of pregnancy 

 consists of a large bag the appearance of which in the living 

 animal has been described by Mr. Jackson. Upon the surface 

 of it large vascular ramifications are seen, and it is subdivided 

 internally into a number of distinct pouches, opening by wide 

 slits into the lower part of the sac. This sac seems to be noth- 

 ing but the widened lower end of the ovary, and the pouches 

 within it to be formed by the folds of the ovary itself. In each 

 of these pouches a young is wrapped up as in a sheet, and all 

 are packed in the most economical manner as far as saving 

 space is concerned, some having their, head turned forwards 

 and others backwards. This is, therefore, a normal ovarian 

 gestation. The external genital opening is situated behind the 

 anus, upon the summit and in the center of a conical protu- 

 berance formed by a powerful sphincter, kept in its place by 

 two strong transverse muscles attached to the abdominal walls. 

 The number of young contained in this sac seems to vary. Mr. 

 Jackson counted nineteen;- I have seen only eight or nine in 

 the specimens sent by Mr. Gary, but since these were open when 

 received it is possible that some had been taken out. How- 

 ever, their size is most remarkable in proportion to the mother. 

 In a specimen of Emb. jacksoni io inches long and 4^ high 

 the young were nearly 3 inches long and i inch high; and in 

 an Emb. caryi 8 inches long and 3^ high the young were 

 2\ inches long and \ of an inch high. Judging from their size, I 

 suspected for some time that the young could move in and 

 out of this sac like young opossums, but on carefully examin- 

 ing the position of the young in the pouches, and also the 

 contracted condition of the sphincter at the external orifice 

 of the sexual organs, I remained satisfied that this could not be 

 the case, and that the young which Mr. Jackson found so lively 

 after putting them in a bucket of salt water had then for the 

 first time come into free contact with the element in which they 

 were soon to live ; but at the same time it can hardly be doubted 

 that the water penetrates into the marsupial sac, since these 

 young have fully developed gills. The size of the young com- 

 pared with that of the mother is very remarkable, being full one- 

 third its length in the one, and nearly so in the other species. 

 Indeed these young Embiotocae, not yet hatched, are three or 



