20 PYCNOGONIDA. 
Arachnide artrogastro (Koenenia mirabilis) rappresentante di un nuovo ordine (Microtelyphonida)» 
(1886), which essay follows the preliminary paper without figures by the same author: «Intorno ad 
un nuovo Aracnide artrogastro (Koenenia mirabilis) che crediamo rappresentante d'un nuovo ordine 
(Microteliphonida)» (1885). As, however, the treatment by Hansen and Sørensen seems to me to 
be far more solid than that of Grassi, and as the figures, in which I take most interest, are very 
fine and distinct, I shall chiefly abide by this treatise written in English, with its plate, to the figure 
2 of which I shall especially refer, as it shows the animal viewed from the lower side. The homology 
of the proboscis of Koenenia (0), which by the authors have been named with the unfortunate ex- 
pression «mouth», while Grassi uses the much better one «papilla boccale», with the proboscis 
of the Protonymphon is conspicuous, and the relation and situation as to the three foremost 
pairs of limbs is exactly the same. Through the proboscis of Koenenia a transition is next formed 
to the mouth-structure in the other Arachnida, where I, contrary to Hansen and Sørensen, and to 
the prevalent opinion, find the same proboscis, and it has only to be pointed out that the proboscis 
in the other orders of Arachnida, on account of its position between the powerful gnathites, necessarily 
must become shorter and more strongly chitinous than in Koenenia; and nowhere, perhaps, is the 
shortening and chitinization so accomplished as in.the Telyphona7) so nearly related to Koenen1a. 
But if the proboscis of Koenenia and thus of the other Arachnida is homologous with that of the 
Pycnogonida, and if it has never been supposed or is impossible to consider the proboscis of Koenen1a 
as formed by a coalescing of oral parts or guathites, then it must be said that there is no reason at 
all to suppose such a coalescing in the proboscis of the Pycnogonida. 
In the figures 7 and 8 is next given a drawing of the proboscis of Koenenia, viewed from the 
side and from below, but without any contribution as to its inner structure; it is only said that «the 
muscles are very strong», and some fine, indistinct lines in fig. 7 may be taken as an indication of 
these muscles. It cannot, however, be doubted that it is a sucking apparatus or a pump, as is also 
shown even by a less strict examination. 
The genera Fa/l/ene and Pseudopallene show in their larval form, as well in the first as in the 
second stage, so great a difference when compared with the other larvæ of Pycnogonida, that there 
might seem to be reason enough to set them up as a particular type; but as the difference chiefly 
consists of a reduction of the embryonal legs or even a disappearing of these, it is morphologically 
of small importance. I have not seen so young a stage as that I have drawn of Pycnogonum littorale 
pl. I, fig. 1 and 2; the youngest ståge I have seen, is that of Pseudop. spinipes, pl. 1, fig. 7, where the 
embryo is viewed from the side, lying in the egg, and with distinetly defined cheliforus, proboscis, 
and foremost pair of ambulatory legs. In the cheliforus, the two outermost joints, the chela, are not 
yet separated, and every trace of embryonal legs is wanting. That the swelling behind the cheliforus 
must be the foremost pair of ambulatory legs, and cannot be one of the two pairs of embryonal legs, 
1) Thus I cannot agree to the comparison between the proboscis («mouth») of Koenexia and the composite mouth, 
with the general addition of the gnathites, of the other Arthropoda, and I think that the difference as to the mouth-struc- 
ture may best be expressed in this manner that, while in the Arthropoda generally more pairs of limbs, the gnathites, close 
together around the oral orifice, and are developed with reference to their partaking in the catching of and preliminary 
dealing with the food, in Koerxerza, as well as in the Pycnogonida, all the corresponding limbs are kept away from the oral 
orifice, which accordingly in these forms is placed freely in the point of the «papilla boccale». 
