1886.] NATURAL SCIENCES OF PHILADELPHIA. 245 



present I place texanus in the synonymy of aculeatus, the pecu- 

 liarities above mentioned being perhaps due to mutilation. 



The many specimens examined by me are from Wilmington, 

 Delaware, and from Woods Holl, Massachusetts. 



The var. cataphractus differs from aculeatus in its deeper and 

 shorter form. Northern specimens are larger and more robust 

 than those found further south, and it is not likely that with a large 

 series any tangible permanent differences could be maintained. 



The names cataphractus and obolarius were given to Alaskan 

 specimens ; the insculptus from the Arctic is not essentially 

 different, and the serratus of Ayres and intermedius of Girard, 

 from further south, are also certainly the same. 



The large collections made by Jordan and Gilbert of the West 

 Coast of the U. S., show conclusively that not more than two 

 distinct forms of Sticklebacks, cataphractus and microcephalus, 

 exist on that coast. 



4. Gasterosteus atkinsii. 



Gasterosteus atkinsii Bean, Proc. U. S. Nat. Mus., 1879, 67 (Schoodic 

 Lakes); Jordan & Gilbert, Syn. Fisli. N. A., 395, 1883 (Copied). 



Habitat. Schoodic Lakes, Maine. 



This species is characterized by the presence of 15 lateral 

 plates ; it is therefore intermediate between the full armed 

 aculeatus and the partly mailed gymnurus, etc. The species is 

 known to me from the description of Bean (loc. cit.). This 

 description indicates some affinity with the European Gasteros- 

 teus semiarmatus, which has also 14 (12 to 15) plates. 



5. Gasterosteus microcephalus. 



Oasterosteus microcephalus Girard, Proc. Ac. Nat. Sci. Phila., 1854, 

 133; Girard, Pacific R. R. Survey, 91, 1859 (Tidare Valley); Sau- 

 vage, Revision des Epinoches, 23, 1874 (Tulare Valley); Joi"dan, Cat. 

 Fresh-water Fish N. A., 443, 1878 ^Name only); Jordan & Gilbert, 

 Proc. U. S. Nat. Mas., 1880, 453 (Puget Sound ; San Francisco ; 

 ]\Ionterey Bay ; San Pedro); Jordan & Jouy, Proc. U. S. Nat. Mus., 

 1881, 1 (San Francisco); Jordan & Gilbert, Proc. U. S. Nat. Mus., 

 1881, 69 (Los Angeles to Puget Sound); Bean, Proc. U. S. Nat. 

 Mus., 1881, 240 (Piseco Lake, Sitka; St. Paul, Kodiak; Chirikoff 

 Isl. ; Iliuliuk Unalaska); Bean, Proc. U. S. Nat. Mus., 1881, 370 

 (Pacific, south of Bering Strait; Puget Sound; San Francisco); 

 Jordan & Gilbert, Syn. Fish. N. A., 395, 1882 ; Rosa Smith, Proc. 

 U. S. Nat. Mus., 1883, 217 (Name only); Rosa Smith, Proc. U. S. 

 Nat. Mus., 1883, 333 (Todos Santos Bay); Bean, Proc. U. S. Nat. 

 Mus., 1883, 353 (Mountain Lake, Alaska); Bean, Cat. Fish, in 

 Internat. Fish. Ex. London, 19, 1883 (St. Paul, Kodiak). 



