^%Y''] PROCEEDINGS OF THE NATIONAL MUSEUM. 09 



Hyas coarctatus Lcacli. 



Hi/as coarctatus Leacli, (Mala. I'odojtli. IJiit., pi. xxi li, figs. 1 and 2, 1815); Trans. 



Linn. Hoc. London, xi, j). 329, 1815. Lcidy, Jour. Pliila. Acad. (2), iii, p. 17, 1855. 



.Stimpson, Bcston Jour. Hnt. Hi.st., vi, p. 450, 1857. Packard loc. cit. (cotfj'c/rt/ft). 



.Smith, Kept. U. S. FishCoiniin-. for 1871 and 1872 (1871). p. .548; Trans. Conn. Acad., 



V, p, 43, 1875) ; Kept. U. S. Fish Coiumr. for 1882 ( 1884), )t. 347 ; for 1885 ( 1887), j). G2(>. 



Lockiiigton, Proc. Cal. Acad. Sci., yii, p.G.5, 1870. Carriugton and Lovctt, 



Zo()logist (3), V, p. 415, 1881. Miers, Cliallouger l\cp<., Zoid., xvii, p. 48, 1S8G, 



(coarctata). and synonymy. Scott, op. cit., p. 2.56. Auriviilius, op. cit., p. 4G, 



pi. 1, fig. G. 

 //)/«« lati/ro»» Stimpson, Proc. Pliilii. Acad. Nat. Sci., ix, p. 217, 1857. Lockingtoii, op. 



( ii., ]). Gl. Smitli, Trans. Conn. Acad., v, p. 45, 1879. Murdoch, Kept, of Expcd. 



to Point Hiirrow, Alaska, ]i. 137, 1885. Auriviilius, oj). cit., p. 4G, (Crcculaud). 



Stiinpson's si)ecic.s lati/rom is based chiefly on the shorter, broader, 

 less acute rostriun, the ch)sed orbital fissures, and the broader anterior 

 portion of the carapace as compared with coarctatus. A large number 

 of specimeus from many different localities along the Atlanti(; and Pa- 

 cific coasts have been examined and the following observations nuide: 

 In the specimens 2 inches or more in length from the Atlantic, ranging 

 from Nova Si.'otia to Greeidand ami from shallow water to 81 fathoms, 

 the rostral horns are short and blunt and the orbital fissures are closed, 

 or in a few specimens very narrowly o[)en, varying in dilferent indi- 

 viduals from the same locality. The widtli of the anterior portion of 

 the carapace is from 0.7G to 0.87 of the branchial width. From Jieiing 

 Sea and the Arctic coast of Alaska vast numbers of large specimens 

 have been obtained by various collectors, including an interesting 

 series from oflt' Bristol Bay collected by the Fish Commission steamer 

 Albatross during the summer of 1890. They are not only variable in 

 width, but the orbital fissures, while usually closed, are not uniformly 

 so. The rostral horns are always rather short, broad, and obtuse. 

 The widtli of the anterior portion of the cara])ace varies from O.Oi) t.) 

 0.85 of the branchial width, the narrowest specimeus being larger than 

 any that have been obtained from the Atlantic. The two series of large 

 specimens from the Atlantic and Pacific coasts are absolutely iiulistin- 

 guishable, as the minor characters mentioned by Stimpson, the swollen 

 carai)ace, the number of tubercles, and the obtuseuess of the angles, all 

 vary with the individual. 



In smaller specimens the orbital fissures are usually open, the ros- 

 trum proportionally longer than in larger forms, and the anterior width 

 is greater, varying from 0.8G to 0.02 of the branchial width. The only 

 European specimens which I have at hand are seven from the Shet- 

 land Islands and one from Kielerbucht. The former are from 1 to 1.] 

 inches in length, have a very long rostrum, wide orbital fissures, and 

 iwv of medium width anteriorly. Tiie merus joints of the ambulatory 

 legsareunusnally long, Thisform, which is probably the typical coarcta- 

 tus, we find reproduced in large numbers on the Atlantic coast of 



