C. H. Treadgold 119 
Taking everything into consideration, the number and arrangement of 
the paired genital papillae would seem to be identical in the two species. 
The spicules (Plate IX, fig. 2, Spic.) differ from those of L. loa in being 
longer and broader, while the proximal ends of both are striated 1 . The 
appearance of their free extremities differs widely from Looss’s description, 
but agrees in some respects with that given by Leiper. 
The larger of the two, which is also the more curved, varies from 0-18 to 
0-246 mm. in length. Its proximal portion is very refringent and has a coarsely 
striated appearance both before and after removal from the body; the non- 
striated terminal portion tapers towards its free extremity, which is sharply 
pointed. The smaller spicule varies from 0-108 to 0-13 mm. in length. Its 
proximal portion is not especially refringent, but shows fine, transverse striae 
which are only visible after the spicule has been dissected out (they are indi¬ 
cated for a short distance by dark shading in Plate IX, fig. 2); the terminal 
portion is fairly substantial and ends rather bluntly, the tip somewhat resem¬ 
bling the end of a crochet needle. The basal portions of both spicules appear 
to have a fine lumen; however, their terminal portions are not canalised but 
grooved, the groove extending almost to the free extremity; in the case of 
the smaller spicule, the proximal end of the groove shows a small fusiform 
dilatation. 
Both these organs are contained in sheaths which open at the ano-genital 
orifice; they may be seen protruding for a variable distance or may be com¬ 
pletely retracted into the body; when projecting to any extent they tend to 
cross one another. Retractor muscles are inserted into their bases, the spicular 
sheaths being lost on their outer surfaces. 
The internal genitalia consist of a tubular testis which terminates in the 
ejaculatory duct; this opens together with the rectum at the anogenital orifice. 
The nearly spherical spermatozoa measure from 5-7 /x in diameter. 
The genital system in the female. The position of the vulva is relatively 
constant, being never less than 2 or more than 3 mm. from the anterior ex¬ 
tremity. 
The length of the vagina is less constant. Ludwig gave it as 3 mm. for 
L. loa. All subsequent workers give it as 9 mm. and cast much doubt upon 
this observation of Ludwig’s. After measuring several which varied between 
9 and 10-5 mm. in length, I came across one which measured only 4-2 mm., so 
that personally I have little doubt as to the correctness of Ludwig’s statement. 
The upper end of the vagina divides into an anterior and a posterior genital 
tube, each of which is subdivided by Looss into uterus, receptaculum seminis , 
oviduct and ovary. He gives a detailed account of these structures with which 
my own observations entirely agree; I will not therefore describe them. 
1 In L. loa, striae are only described for the larger spicule. 
