18 PYCNOGONIDA. 
free joint is round and slender, and the second, or outermost, joint is always still thinner, most fre- 
quently claw-shaped, and of about the same length as the preceding joint; sometimes, however, this 
second joint is prolonged to a long, thin thread more than twice the length of the body, as for inst. 
in Phoxichilidium femoratum, pl. I, fig.4. The growth of the embryonal legs soon ceases, and even if 
they, as is often the case, are kept in the following larval stages, they show 10 alteration. 
The proboscis, like the embryonal legs, begins as a low protuberance, soon growing into 
a conical process with more or less tapering sides, but without trace of any inner or outer division, 
far less of a coalescing of constituent parts. The pharynx, however, is early developed, already in 
this larval stage, and it is seen as a dark line stretching from the point of the proboscis towards its 
base, as in Wymphon longitarse, pl. II, fig. 20, and in Nymphon macronyx, pl. II, fig.g. The chitinous 
ridges serving for the insertion of the Musculi retractores of the pharynx, are also early developed. 
With regard to the interpretation of the proboscis I shall take the liberty to state my opinion 
already in this place, although my interpretation is chiefly due to the structure of this organ found 
in a much more advanced stage of development and especially in the imago. It is the unhappy note 
by Latreille to his description of the Pycnogonida, Régne animal, éd. II. Tom IV (1829) which is 
found again and again. The note, 1. c. p. 276, note 3, runs thus: «Le siphon ... m'a offert des sutures 
longitudinales, de maniére qwil me parait composé du labre, de la languette et de deux måchoires, le 
tout soudé ensemble». It was to be thought that Dohrn:) had succeeded in demolishing this notion, 
and I can with all my heart agree with him, when in «Pantopoden des Golfes von Neapel» (1881) he 
says: «Wir wurden . .. keinenfalls aber an eine Verschmelzung von extremitåtenartigen Mundtheilen 
zu denken haben», l.c. p. 109. We find nevertheless that Adlerz in his fine little essay, Contributions 
to the Morphology of the Pantopoda («Bidrag till Pantopodernes Morfologi» (1888)) tries to maintain 
the old view of Latreille. Adlerz founds his arguments especially on the fact that the two low- 
ermost «antimeres» (Dohrn) of the proboscis receive nerves from special centra in the first abdominal 
ganglion, comp. his fig. 2 on pl. I, and the letters « and wg in this figure. For these two foremost 
centra with their fibrillous «punctuous mass» (Leydig: Punktmasse) in connection with the two 
pairs of centra behind them in the same ganglion should show, how this ganglion is composed of 
three original pairs of ganglia, but it is well known that to each pair of ganglia belongs a metamere 
with a pair of limbs, which metamere could not then be anything but the two lowermost «antimeres» 
l.c. p.10. To this is to be answered that, as no trace of limbs has ever been seen that might corre- 
spond to or be merged in the two antimeres, as little has any trace been found of a pair of foremost, 
free ganglia; besides it has to be remembered that the supply of nerves for the two lowermost meta- 
meres most properly must be said to arise from the foremost one of the two, originally separated, 
but now coalesced pairs of ganglia, in which, but not until a later stage, the corresponding foremost 
pair of centra have developed. This view would also agree with my examinations, as I have also 
found the ganglia to be originally uniform, and not until later showing distinct centra with their 
fibrillous «punctuous mass» running into or stretching into the nerves of the limbs. I think upon 
the whole that as to the morphology too great stress is at present laid upon the ganglia, and my 
7) Already Zenker in «Untersuchungen iiber die Pycnogoniden» (1852) has p. 383 seq. rejected the supposition of 
Latreille, referring to the representation given by Krøyer of the occurrence of the proboscis in the young larva. 
