ARANEIFORM CRUSTACEA. PYCNOGONIDJE. 



287 



nervous system, and four eyes placed upon a tubercle on the an- 

 terior segment. Their minuteness renders it difficult to as- 

 certain many^ points of their structure ; and much is still to 

 be learned respecting them. Various species exist on our 

 own coasts. Their motions are remarkably slow, and appa- 

 rently difficult; and it is obvious from this circumstance, as 

 well as from the conformation of the mouth, that their prey 

 must consist of either dead animal matter, or of living animals 

 as defenceless as themselves. 

 The body consists of a sort 

 of cephalothorax, composed 

 of four segments, each bear- 

 ing a pair of legs ; it is 

 terminated in front by a 

 conical rostrum, often ac- 

 companied by a pair of pal- 

 piform organs, and behind 

 by a minute abdomen. The 

 females are distinguished 

 by the possession of a pair 

 of spurious legs (Fig. 619), 

 placed in front of the rest, 

 and appropriated to the 



purpose of holding and carrying the eggs. These |re collected 

 into globular masses, enveloped with a thin skin or membrane, 

 each mass being firmly adherent to the limb. There are several 

 of these masses in most species of the tribe ; but in Pycnogonum 

 itself, the eggs form a single broad square membrane laid under 

 the body. Of the development of these curious animals we know 

 scarcely anything, except that the young on leaving the egg are 

 only furnished with four short legs beset with long filaments, so 

 that they must undergo considerable changes' before reaching 

 maturity. With regard to their habits, our information is equally 

 deficient. 



FIG. 619. NTMPHON GROSSIPES, and under side 

 of its Beak. 



