ON THE DEVELOPMENT OF PYCNOGON. 125 
of attention. Many naturalists, during their investigations, 
must have noticed and recorded certain facts bearing upon these 
points; but it unfortunately happens that these have either re- 
mained unpublished, or inaccessible to the ordinary student, 
who is therefore left to grope in the dark, and to rely upon his 
own observations and research, for any knowledge of this interest- 
ing subject that he may be desirous of obtaiming. Little has 
been said of the anatomical differences of the sexes; we only 
know that most, if not all, of the females of the several species 
possess an additional pair of members, anterior to the ordinary 
feet. These members, known by the name of ‘ false feet,’ differ 
_ in different genera, have been made an important aid in classifi- 
cation, and are furnished with a number of sete, of forms vary- 
ing according to the genus or, it may be, species; and near to 
these sete, at certain periods, the eggs or ova are found. 
We know nothing of the earliest stage, or means by which 
the ova are produced and fertilized; and, so far as I am aware, 
the subject has not been alluded to by any writer on these ani- 
mals. The only published record to which I have had access is 
a paper by Kroyer in the ‘ Annales des Sciences Naturelles’ for 
1842, being “ Notes on the Metamorphosis of the Pycnogonides,” 
wherein the larval forms, as attached to the females of Pycno- 
gonum littorale, Nymphon grossipes, and Phoxichilidium femoratum, 
are figured and described. I have also been kindly favoured by 
Mr. Spence Bate with some MS. notes “ On the Morphology in 
the Development of the Pycnogonide,” which were read at the 
British Association Meeting of 1855. These authors, however, 
go no further than the larval forms, and make no allusion to the 
subsequent stages through which the young animals pass before 
they attain the mature state; therefore the following observations, 
although imperfect in some most important particulars, may 
perhaps be the means of guiding others in the search, and thus 
ultimately lead to the complete elucidation of the development 
of the Pycnogonoidea. 
The species that afforded me material for the following ob- 
servations, and which I believe to be Phoxichilidium coccineum 
