57 
skin, and there can be no doubt that they take nourishment through their well-developed mouth 
(s. later on under Spher. danica.) They are always considerably depressed, the anterior 
margin is long, now quite straight, now a little concave, in the younger specimens occasio- 
nally a little convex; the lateral margins converge rather considerably backward and merge 
more or less evenly into the posterior margin. The mouth is pretty well developed, with 
distinct mandibles (fig. 1g), and is situated much to the front on the ventral surface; it is 
surrounded by rather small pouch-like processes: antennule (a), antennze and maxille, and 
behind it is found a rather large, peculiar area. Near the anterior margin on the ventral 
surface is seen a body with an irregularly curved posterior margin, and this is the adhesive 
plate (s), by which the animal is hinged. The parts just described on the ventral surface 
are surrounded by a naked area, whereas the greater part of the remainder of its surface 
is provided with hairs, which are sometimes arranged in rows of two or three or more, 
sometimes are more scattered, and the hairs which grow close to the edge are rather long, 
the more central ones are short; the larger part of the dorsal surface is naked. Fig. 1i 
and fig. 1k reveal that the contents of the pupa — perhaps on account of alcoholic influence 
— do not reach the outer skin, whereas fig. 1h shows a very large and entirely filled 
pupa; fig. 1i, the specimen represented on a larger scale, so far shows the same as the two 
illustrations just mentioned, but it reveals at the same time that the inner body has its 
own skin with distinct sets at its margin. The male of Choniostoma being wnknown, | 
cannot decide how far all the specimens found are only female, or both female and male pupz. 
We now come to a species — Spheronella paradoxa — whose development differs 
very much from that of Spher. Giardii, or that of Homoeoscelis minuta, and the forms 
which, according to my just stated (though rather defective) knowledge, are related to these 
species. In Spher. paradoxa both sexes develop themselves without passing through the stage 
of an independent pupa properly speaking, nevertheless there is a considerable difference of 
aspect between the development of the sexes. Let us first examine the development of the 
male. I had a very considerable material of larvee, which were hinged by their front, and 
in which the cephalothorax was nearly as broad as long, besides being very thick (pl. LV, 
fig. 1d); however, as it was impossible to me, in spite of careful searching, to find a single 
male pupa, I conceived the idea of submitting my big larve to a thorough examination, and 
in a single specimen I fancied that I saw two spermatothece through the skin. I succeeded 
in taking away the skin of this larva, and I found a young male with hairs on its abdomen, 
rather short caudal stylets, and two spermatothecse, whereas the limbs were still for the 
most part rather indistinct. Hereby, then, we have got the proof that the males come out 
directly of these big larve (comp. Aspidoecia, p. 54), still there remains a single point which is 
not fully explained. My rather numerous males are — with very rare exceptions — about 
245 and -27 mm. in length, though one of the big larvee is only ‘19 mm. long, the empty 
abdomen included, and the cephalothorax of one of the largest of these larvee is only “16 mm. 
in length (in pl. ILI, fig. 4¢ I have represented a male, in fig. 4e such a larya enlarged on 
8 
