76 THE CYPRINODONTS. 
dans les autres. Dans le mile, les uretéres donnent dans la vessie fibreuse, 
dans laquelle les laitances versent la liqueur séminale; dans la femelle, c’est 
X\ Vextrémité de ’oviducte. On doit se rappeler que, dans tous les autres 
poissons, l'urine sort par un orifice distinct de celui de l’ovaire ou des lai- 
tances.” ‘La communication entre la vessie et les sacs de la laitance est de 
plus manifeste par la simple insufflation.” “On peut donc la considérer 
comme une vessie urinaire, parce qu’elle recoit les uretéres, et en méme 
temps comme une sorte de vésicule séminale, ot le canal déférent des tes- 
ticules verse la laitance.” Such is the description one might take from the 
outside (see Plate VI. Fig. 11). A very different story is to be taken from 
the interior (Fig. 12, 13). The receptacles for the urine and for the semen 
are really distinct ; they are separate to the base of the first anal ray, where 
their ducts join ina common tube. The muscular valve (a, Plate VII. Fig. 
6, 11-13) at their junction represents the external openings on males of such 
cyprinodonts as do not possess the added canal common to seminal and 
urinal discharges. This common canal recalls the structure in similar use 
among higher vertebrates. A structure almost identical, corresponding so 
far as concerns the common tube on the anal fin, is seen on the females of 
certain Funduli, F. heterochtus for instance, on which ovaries and bladder 
empty into a single tube at the base of the anal, the tube being extended 
downward upon the first anal ray half or more of the length of the fin. The 
erowth of the tube in the young male of Anableps, also, presents much simi- 
larity with that seen on the females of these Funduli. In the early stages, 
sketched on Plate VII. Fig. 7-9, at different ages, the anal of these young 
males shows close resemblances to that of the adult female in the other genus. 
The advance from the ordinary in each case, before the male fin itself trans- 
forms, is simply the extension of the tube downward, beyond the separate 
ducts, along the anterior edge of the fin. A band of inelastic tissue (p) 
crosses the neck of the bladder immediately behind the urinary chamber, 
above the origin of the tube through which it empties, m such a manner 
that by contraction of a muscle at each end of it, lying just outside of each 
ventral fin, the urine is prevented. from escape while the contents of the semi- 
nal chamber are forced out through the valve (x) and the tube on the anal 
fin (Plate VII. Fig. 6, 15). The great muscles (7) controlling the move- 
ments of the anal of the male lie close behind and above the bladders and 
no doubt also act as compressors. The arrangements for keeping the semen 
separate from the urine are decidedly effectual. The bladder of the female, 
