SEVENTH LECTURE. 



^xy^^c 



THE RELATIONSHIPS OF THE SEA- 

 SPIDERS. 



By T. H. morgan. 



Amongst the Hydroids and sea-weeds on the piles 

 of the wharf of the Fish Commission, hving below the 

 tides, and dinging tenaciously by means of the long 

 jointed legs to the surrounding stems, are to be found 

 abundantly small whitish spider-like creatures. And if 

 the sea-weeds, etc., dredged in the ''Hole" be examined, 

 a similar but larger animal may be found.^ The group 

 to which these belong is known technically as the 

 Pycnogonida, or, as Professor Dohrn of Naples has 

 proposed to call them, Pantopoda. Fortunately we have 

 a good enough English equivalent for the terms — Sea- 

 Spiders. 



It may not be out of place to say here a few words 

 about the structure of the adults of these sea-spiders, 

 as the group is a small, isolated one, and only short 

 accounts are given in the ordinary text-books. The 

 accompanying figure (i) may aid us in understanding 

 some of the principal structures of the group. 



1 Phoxichilium maxillare. 

 142 



