62 
antennule; according to this interpretation they ought to have been marked »a« in the 
illustration, and the antenne not »ac, but »c«. Somewhat behind the fixation-thread I 
found a pair of bodies (z) which were situated at a short distance from each other and 
looked as if they were pasted on; whether they belong to the animal [ do not know, though 
T suppose they do, as one of the specimens was provided with both these small bodies, the 
other with one of them. The hindmost part of the body and a smaller part of the surface 
surrounding the large ventral process, are provided with a number of rather short hairs. 
Fig. 1¢ in pl. XIL shows the stage of development which immediately precedes the 
afore-described stage. The only specimen found is 24 mm. long; the scale of enlargement 
is like that of the last stage. The body has about the same shape, and the mouth, the 
maxilla, maxilla (f), maxillipeds (g) and antennz (a) have a similar structure and position; 
but the antemule (t) are placed further backward than in the more advanced stage, almost 
behind the middle of the animal; their form is somewhat vague. The dorsal fixation-thread 
(u and v) proceeds at some distance behind the middle of the median line of the back; it 
is almost constructed as in the older stage, but is considerably longer, and its distal part 
is much less stout. The crescent of the genital aperture (r) is not found on the dorsal, but 
on the ventral surface, near the posterior extremity of the body. The odd ventral process 
(x) is situated almost in the middle between the base of the maxillipeds and the posterior 
end of the body; it is rather short and very stout and broad; it is indeed a projection, 
which has on its top a well-developed mouth (y) with mandibles, and whose sides and front 
part are provided with chitinous lists, like those which surround the mouth of the pupa in the 
group Spher. Leuckartii; on the side this skeleton forms a figure (y’), which, seen as in 
the drawing obliquely sideways, looks very much like a maxillula; however, on closer 
examination it turns out not to be any appendage. Now we should feel much inclined 
to think, that the pupa just described does indeed represent an animal provided with an 
apical mouth in the act of breaking out of the skin of the pupa, the mouth of which is 
marked »y«, however, repeated and careful examinations of the admirably preserved pupa, 
which L have been able to roll under a glass-cover, and to study from all sides, give the 
result, that 7 as really an animal with a larger apical and a smaller, but very well developed 
ventral mouth, the latter of which disappears in the following stage, only leaving the odd 
ventral process x in fig. 1d. That the existence of two mouths in the same animal is per- 
fectly incomprehensible to me. goes without saying. — The whole animal is naked. 
Finally I have found two badly preserved, infinitety small pupz of about equal size, 
one of which is illustrated in pl. XI, fig. 3i. The body is 136 mm. long, shortly ovate, 
with a well-developed mouth at the rather pointed front extremity, and a little more back- 
ward on the ventral side maxille and maxillipeds, the former of which being of pretty good 
size, but with thin walls and of a somewhat vague form, whereas the maxillipeds are almost 
smaller than the maxillee, 2-jointed, and very weak. Beneath the skin, between the maxillz, 
is seen a pretty large, anteriorly inflexed ring (x), which seems to be the beginning of a 
