XV.-REPORT ON THE PYCXOGONIDA OF NEW ENGLAND AND 

 ADJACENT WATERS, 



By Edmund B. Wilson. 



' It is intended to give in this report an account of our present knowl- 

 edge of the species of Pycnogonida known to occur upon the coasts of 

 New England and Kova Scotia, comprising descriptions and figures of 

 ail the forms, and an account oi their geographical and bathymetrical 

 distribution. Although the work is mainly systematic, and has been 

 done with special reference to supplying a basis for satisfactory deter- 

 dinatioiis of the genera and species, and their distribntion, it has been 

 thought best to give also a brief general account of the structural pecu- 

 liarities and general natural history of the group. lu so doing I have 

 drawn largely from the works of several other writers ; and especially 

 from those of Dr. Anton Dohrn, who has made a careful study of the 

 anatomy and embryology of these animals. It should be borne in mind 

 that the stracture of the Pycnogonida is, as yet, not well understood, 

 and that further research is needed to fully explain the anatomy and 

 systematic relations of this peculiar and perplexing group. To make the 

 report as complete as possible, it has been made to include not only the 

 collections of theFishCommissionjbut also those made by various other 

 parties since the year 1864. The parties referred to were as follows : 

 Expedition of 1864, Professors A. E. Yerrill and S. I. Smith ; Expedition 

 of 1868, the same with the addition of Professor H. E. Webster and Mr. 

 Geo. A. Jackson; Expedition of 1870, Professor Verrill with Mr. Oscar 

 Harger and Mr. C. H. Dwindle. The Pycnogonida from these sources, 

 with those of the Fish Commission collections, are at present preserved 

 in the Peabody Museum of Yale College, where they have been studied. 

 I take pleasui-e in here expressing my great obligations to Professors 

 Verrill and Smith ; I am also indebted to Professor Carl Semper for 

 specimens of several European species. 



The Pycnogonida form a small and very natiu-al group of articulated 

 animals, which are all marine, have a very wide geographical distribu- 

 tion, and are found at all depths from low-water mark down to many 

 hundi-ed fathoms. Although forming a small and inconspicuous group, 

 they possess a special interest from peculiarities in their structure and 

 development; and though some of the species have been carefuUy 

 studied by competent observers, opinion is yet divided as to the exact 

 position they should occupy in the zoological system. By some writers 



463 



