PYCNOGONIDA. 



The oculiferous segment of Wilson and the Augensegment> of Bohni is only another 

 expression taken from the appellation of Kroyer, but applied to the whole of the first segment of 

 the trunk. When Erichson uses the name of Kopf for this part of the body, it is exclusively with 

 regard to the ambulatory legs and the comparing them to the limbs of the Arachnida, of which again 

 the three last pairs were to correspond to the thoracical legs of the Insects, while all the correspond- 

 ing' segments were to form the thorax. 



Oculiferous tubercle {tuber ocular r), fig. I, o. 



Kroyer: 0ieknude (protuberantia ocularis); Sars: Oieknude (tuberculum oculiferum). 



On the dorsal side of the first segment of the trunk, in the middle of it, but more or less 

 backward, is found a knob-like protuberance, the oculiferous tubercle. The shape of this knob is very 

 different, varying in the different genera and species, growing from a low, rounded swelling to a 

 height of almost the length of the trunk, and ending with a tapering point. It is not until the second 

 larval stage of development that the oculiferous tubercle begins to be seen as an excrescence on the 

 first segment of the trunk after this segment being distinctly separated. The eyes make their 

 appearance prior to the oculiferous tubercle on the spot of the first segment of the 

 trunk, from which this latter rises, and during the growth of the tubercle the eyes are raised with 

 it more or less, so that in the imago they are placed in a square round the tubercle, more or less distant 

 from its top. The tubercle bears typically four single eyes, ocelli, but frequently the eyes are not, or 

 only a little, developed, so that as well blind species as seeing ones may be found in the same genus 

 (Colosscudeis). 



Neck (coll urn), fig. I cl. 



I have thought it best, like Sars, to keep this name for the middle part of the first thoracical 

 segment, when it is more or less strongly marked off, as I regard this appellation as so little marked, 

 that it is no necessary consequence to look upon or denominate as head the thickened part of the 

 trunk King before the segment in question. 



Lateral process of the first segment for the insertion of the ovigeroiis legs 

 (protuberantia pedis ovzferi), fig. I apo. 



Sars: Halsfortsats (processus colli) til Fseste for de falske Fodder. 



This process originates from the under side of the first segment of the trunk just before the 

 process of the trunk; it is very short, inconspicuous, and from its outer side or point arises the 

 ovigerous leg. When the segment of the trunk is short, so that there is no neck, the palpi get 

 towards it, and in some genera (Colosscudeis) the palpi do apparently arise from the fore side of 

 this process. 



Second segment of trunk {segmentum corporis secundum), fig. i c 2 . 



Third segment of trunk (segmentum corporis tertium\ fig. i d. . 



Fourth segment of trunk (segmentum corporis quartum\ fig. i c4. 



No synonyms are here necessary to explain the opinion of the authors as to these segments. 

 It is a matter of course, and everybody agrees that they are homonomous with the first segment of 

 trunk, or, at all events, with the large upper and hinder part of it. 



Caudal segment (segmentum caiidale), fig. i sc. 



