Pycnogonida. 
By 
Fr. Meinert. 
he species represented in the following treatise have, with the exception of one only, been all 
Æ taken on the «Ingolf»-expedition. The said one species is Fa/l/enopsis fluminensis Kr., which 
has "been included in order to elucidate the genus, and throw light on this much disputed species, the 
original of which is still found at the Zoological Museum. The material for the «developmental 
history» has likewise mostly been taken on the said expedition, although some few species have been 
taken from earlier collections. The number of species taken on the «Ingolf»-expedition is 31, of 
which 8 are new to science. When 43 species are drawn and described by G. O. Sars in «Den norske 
Nordhavs-Expedition, 1876—78», it is to be remembered that only 20 out of these 43 species are due 
to the collections of the expedition. 
Terminology. 
Although the terminology of a group of animals chiefly depends on the systematic position 
of the group, and the homologies and analogies founded on this position, on the other hand it will 
be necessary to begin with definite appellations for each of the organs, though these appellations can 
only be justified by the later examination and the systematic position founded thereon.+ I therefore 
shall begin with giving a list of the names I have chosen; and as I here chiefly follow the appella- 
tions given by Sars, so I also take the liberty to copy his figure, Pycnogonidea, 1891, p. 3, which 
will be found on the other side. 
From the two lists it will immediately be seen that I have not thought myself justified in 
following Dohrn, when he, more particularly after Savigny, gives to the limbs a continuous 
numerical order, Extremitas I—VII. This way of designing the limbs has several advantages, and 
has also been followed by later authors, as Adlerz and Schimkéwitsch, but it has also important 
defects, which make themselves strongly felt. It is an advantage of the terminology of Dohrn that 
it is independent of all systematism; to this terminology it is all the same, whether the Pycnogonida 
are Crustacea or Arachnida; it has not to be altered to-day, that to-morrow, when another systematic 
taste is ruling, it may return to the expressions of yesterday, more or less altered in the interval. It 
is, however, inconvenient, when one or more of the seven pairs of limbs (extremities) are specially 
The Ingolf-Expedition. MI. 1. I 
