ON AMPHILINA PARAGONOPORA 55 



duct is known as the ootype (otp). The uterus (u) is continuous 

 with the ootype and is a thin-walled much convoluted duct of 

 wide diameter (capable of great expansion when filled with 

 grown larvae), considerably more than three times the length 

 of the entire body (taking the convolutions into account) 

 and having the characteristic conformation shown in the 

 figures — a conformation which is found in all five species of 

 Amphilina. The ducts lying in the proximity of the ovary — 

 from the receptaculum seminis to the beginning of the uterus — 

 are embedded in a dense cushion of connective tissue (ct), 

 probably protective in function. The common vitelline duct 

 is formed by the junction of the vitelline ducts (vd) of the 

 two sides of the body and all run dorsal to the ovary and 

 the uterus. The vitellaria (vit) extend, as shown, in a row 

 along each edge of the body for nearly its entire length (PI. 3, 

 figs. 8, 14). 



The uterus does not contain eggs until the worm is at least 

 30-35 mm. in length, and then unsegmented eggs are only 

 present at the very commencement of the uterus, the rest of 

 the uterus being quite empty (observed in three specimens). 

 In a worm about 41 mm. long about a quarter of the first 

 (proximal) limb of the uterus is filled with embryos in the 

 blastomere stage of development — groups of four, eight, and 

 twelve blastomeres having been observed. In a worm circa 

 75 mm. long, the uterus is full of eggs in various stages of 

 development, but mature larvae are not present. In the worm 

 which I described as in the act of escaping from the fish through 

 the body-wall and which was more than 130 mm. in total length, 

 mature larvae in large numbers were found in the terminal 

 (third) limb of the uterus, the other two limbs containing larvae 

 in earlier stages of development. I may mention that I have 

 observed the larvae escaping from the uterus to the exterior 

 in an Amphilina not more than 100 mm. in length. 



The testes (tes), as shown in PI. 3, figs. 8 and 13, consist, 

 on each side of the body, of a row of sacs (PI. 3, fig. 13) opening 

 at frequent intervals into the convoluted vas deferens (sd). 

 They lie just internal to the row of vitellaria, and, like these, 



