PYCNOGONIDA. 



antennae; Hoek: mandibules; Hans en: Kindbakkean tenner (antennae mandibulares , also mandibulae) ; 

 Morgan: chelicerse; Sars: Saxlemmer (chelifori). 



The chelifori are the foremost of the three pairs of embryonal limbs, and in most Pycnogonida 

 they grow on, and are kept to the stage of the imago. Only rarely they are thrown off during one 

 of the larval stages (fam. Phoxichilidce, - - in Pycnogonum already on the second larval stage, pi. I, 

 fig. 4), or by the last casting of the skin in the young (Colossendeis angusta and gracilis). They are 

 often more or less rudimentary, especially in the outermost joints {Ascorhynchidiz). Their resemblance 

 to the first pair of limbs in the Arachnida is conspicuous, and there can be no doubt of their impor- 

 tance with regard to the systematism. This consideration has also asserted itself in the appellations, 

 used for these limbs by most authors, and when nevertheless these appellations are so different, the 

 reason may be sought in the fact that also the foremost limbs of the Arachnida have very different 

 names; but as I think the names of antenna, mandible, or mandible-antenna in the Arachnida to be 

 equally objectionable, I have preferred partly after Kr0yer, and together with Sars to use the ap- 

 pellation of cheliforus for the whole limb. 



Scape (scapus), fig. i s. 



Kr0yer: Grundled (articulus basalis); Sars: Skaftet (scapus). 



The cheliforus is divided into two chief parts, a basal or advancing part, and a terminal or pre- 

 hensile part. Of these the former sometimes is undivided, sometimes bipartite. The bipartition is 

 generally distinctly shown by a suture and by muscles, and but rarely it is only more or less indi- 

 cated, so that it may be doubted whether the scape has one or two joints (Pallenopsis). 



Chela or hand (chela\ fig. i ch. 



Kr0yer: Sax (chela); Haiisen: Tang or Sax (chela); Sars: Sax (chela). 



By the appellation chela or hand is designated the second chief part of the cheliforus, and it 

 will, on account of the systematism, be necessary to give special names to the separate parts. I have 

 supplemented the appellation by Kroyer and Sars of the second chief part of the cheliforus by the 

 expression hand, because the separate parts, of which it consists, are named with appellations from 

 the hand. The chela or hand is the two outermost joints of the cheliforus, the first of which forms 

 a proportionally broad part, sending out laterally a long tooth- or finger-shaped process, which towards 

 the point meets with the point of the movable last joint. The hand may be more or less rudimen- 

 tary, or even wholly disappear. 



Palm (pali/ia), fig. i pint. 



Kroyer: Palmen (palma); Han sen: manus; Sars: Palmen (palma). 



Immovable finger (acumen v. digitus immobilis}, fig. i dim. 



O. Fabricius: acumen; Kr0yer: ubevsegelig Finger (digitus immobilis); Hoek: griffe immo- 

 bile des mandibules; B0hm: der unbewegliche Finger; Han sen: poll ex; Sars: den ubevsegelige 

 Finger (pollex). 



O. Fabricius already felt impelled to distinguish between the immovable finger of the hand 

 and the movable outer joint of the cheliforus, and called the former acumen, instead of which expres- 

 sion Kr0yer used immovable finger (digitus immobilis); Sars and Han sen, I think after him, 



