1886.] NATURAL SCIENCES OP PHILADELPHIA. 239 



2 a. E. inconstans cayuga. 



Eucalia inconstans, var. cayuga Jordan, Man. Vert., ed. i, 249, 1876 

 (Cayuga Lake) ; Jordan c% Copelaud, Checklist N. A. Fresh-water 

 Fish, 141, 1876 (Name only); Jordan, Geol. Report Ohio, 998, 1882. 



2 b. E. inconstans pygmaea. 



Gasterosttus pygmmis Agassiz, Lake Superior, 314, 1850 (Lake 



Superior). 

 Eucalia inconstans, var. pygmcea Jordan, Man. Vert,, ed. i, 249, 1876 

 (Copied); Jordan & Copeland, Checklist N. A. Fresh-water Fish, 

 141, 1876 (Name only); Nelson, Bull. Ills. Lab. Nat. Hist., i, 42, 

 1876 (Lake Michigan). 



Habitat Fresh waters of North America, from Kansas and 

 Great Lake region northward to Greenland. Var. cayuga in 

 tributaries of Lake Ontario. Var. pygmseus in Great Lakes. 



The specimens of the typical inconstans examined by me are 

 from Rock River, Illinois. 



Those of the var. cayuga are from Syracuse, New York. 



The micropus of Cope would seem to differ in its shape, being- 

 shorter and deeper, and in having a smaller post-pectoral plate 

 and ventral spines. All of these characters are of doubtful per- 

 manence. 



The globiceps of Sauvage offers no peculiar characters. 



The var. cayuga seems to differ from inconstans in having 

 longer ventral spines and smaller post-pectoral plates ; it is per- 

 haps identical with it. 



The pygmaea of Agassiz is said to differ from inconstans in 

 having the body shorter and deeper, and in the number of fin 

 rays. The difference in form is of no importance, and it is not 

 likely that the alleged difference in the fin rays is real. 



3. GASTEROSTEUS. 



Oasterosteus Avtedi, Gen. Pise, 52, 1738. 



Gasterosteus LinniBus, Syst. Nat. Ed. x, i, 295, 1758 (aculeatus). 



G aster acanthus Pallas, "Zoogr. Rosso, Asiatica, iii, 228," 1811 (cata- 



phar actus). 

 Leiurus Swainson, Nat. Hist. Class Fishes, ii, 242, 1839 (gymnurus, etc.). 



This genus is distinguished from Pygosteus and eucalia in hav- 

 ing the posterior margin of the gill membrane joined to the isth- 

 mus. The body is more robust ; the spines and innominate bones 

 much stronger ; the pubic bones ver}- broad and little divergent. 

 Its species are the strongest of the sticklebacks and the most 



