Pycnogonida. 



By 



Fr. Meinert. 



The species represented in the following treatise have, with the exception of one only, been all 

 taken on the Ingolf-expedition. The said one species is Pallenopsis 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 Schimkewitsch, but it has also important 

 defects, which make themselves strongly felt. It is an advantage of the terminology of Dohru 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. III. I. I 



