334 REPORT OF COMMISSIONER OF FISH AXD FISHERIES. 



This species was dredged by Mr. J. F. Whiteaves in the Gulf of St. 

 Lawrence ! at a depth of 220 fathoms muddy bottom, and has not yet been 

 found on the coast of New England. It is introduced here from the 

 probability that it will yet be discovered in the deeper parts of the Bay 

 of Fundy, where the allied Munnopsis typica M. Sars has already been 

 found, or even in the Gridf of Maine. 



Specimens examined. 



1938 

 1939 



Locality. 



Gulf of St. Lawrence 

 Gulf of St. Lawrence 



220 

 220 



Bottom. 



Mud. 

 ...do 



When col- 

 lected. 



Receivedfrom — 



J.r.Whiieavea 

 -do 



Speci- 

 mens. 



No. Sex. 



d9 



Dry. 

 Ale. 



Ale 

 Ale 



Hyarachna G. 0. Sars. 



Mesostenus G. 0. Sars, Clir. Yid. Selsk. Forh., 1863, p. 211, 1864. 

 Hyarachna G. 0. Sara, Christ. Fjord. DybvaMs-fauna, p. (44), 1869. 



Body scarcely depressed, subpyriform as seen from above, narrowed 

 behind 5 its anterior division separated from the posterior by a deep 

 constriction. The head is large and broad and without a rostrum. 

 Antennulsd short, with a flagellum comx)osed of but few segments. An- 

 tennce exceeding the body in length, with a multiarticulate flagellum. 

 Mandibles short and strong, entire at the apex ; molar process armed 

 with a few setiform spines ; palpus either small and three-jointed or want- 

 ing. Foiu' anterior thoracic segments short, excavated above and fnr- 

 nished with lateral processes directed forward; the three following 

 convex above and destitute of lateral processes ; the antepenultimate 

 scarcely narrower than the anterior segments and deeply emarginate 

 behind. First pair of legs nearly as in the preceding genus ; second 

 I)air unlike the others and usually more robust ; the following two sub- 

 equal and commonly much elongated ; fifth and sixth pairs of legs much 

 as in Bury cope; the last pair unlike the preceding, long and slender, 

 with the segments scarcely flattened, and armed with a long curved claw. 

 Pleou narrowly triangular, pointed at the apex. Abdominal operculum 

 large, covering nearly the whole of the under surface of the pleon, pro- 

 vided with a median crest and numerous marginal setoe. Uropods simple, 

 appressed to the pleon. 



For the generic description given above I have depended almost en- 

 tii^ely upon the work of Dr. G. O. Sars, who originally described the 

 genus under the name Mesostenus. That name being preoccupied he 

 subsequently changed it to Hyarachna. 



