450 Stimpson on the Crustacea and Echinodermata 



dredged on a muddy bottom at the depth of thirty fathoms, 

 off Cape RomanzorT. It was also found in Behring's 

 Straits, by Commodore Rodgers, of the North Pacific 

 Expedition. 



It is in the Museums of the Boston Society of Natural 

 History, of the Smithsonian Institution, and of the Jardin 

 des Plantes.* 



HYAS COAKCTATUS. Leach. 



Hyas coarctatus, Leach ; Malac. Pod. Brit., PI. XXL b. Milne-Edwards j Hist, 

 Nat. des Crust., i. 312. Brandt ; Sibirische Reise, i. 79. 



Dredged off Cape Romanzoff by the North Pacific Ex- 

 pedition. 



This is an arctic species, found on both boreal shores of 

 the Atlantic. It is also the most common crab found in 

 Behring's Straits, and is reported to exist on the shores of 

 Kamtschatka and in the Sea of Ochotsk. 



Mus. Smithsonian. 



HYAS LYRATUS. Dana. 

 Hyas lyratus, Dana ; U. S. Exploring Expedition, Crust., i. 86, PI. I. f . 1. 



Distinguished from the preceding species by the broad, 

 wing-like, antero-lateral expansions of the carapax. It in- 



* As it is always desirable to know where typical specimens may be found for 

 comparison, I shall indicate in every case the different museums in which exam- 

 ples of the species herein catalogued are deposited. Eor convenience, the fol- 

 lowing abbreviations will be used : — 



Museum of the Boston Society of Natural History . Mus. Bost. Soc. 

 '■ " " Smithsonian Institution . . . . " Smithsonian. 

 M u u Philadelphia Academy of Natural Sciences " Phil. Acad. 

 " " " U. S. Exploring Expedition ..." Expl. Exped. 

 " " " California Academy of Natural Sciences " Cal. Acad. 



" " Yale College " Yale. 



a k « Imperial Academy of St. Petersburg . " Acad.Petrop. 



" " Berlin . . . . . . . . " Berlin. 



" " the Garden of Plants at Paris . . . . " Paris. 



« « " Eoyal College of Surgeons, London . . " K. C. S. 

 " " " Zoological Society of London . . . " Zool. Soc. 

 British Museum " Brit. 



