130 NATURAL HISTORY OF ARCTIC AMERICA. 



in the total, auti about equals twice its own length. Whea exi^anded, 

 the pectoral extends usually to the 7th dorsal spine (6th to 8th). 



The distance of the ventral from the tip of snout slightly exceeds -^o of 

 length of body. The length of the ventral spine is always a little less 

 than ^ of the length of the head. 



Eadial formula.— D. IX-XI, 1, 10-11 ; A. 1, 9-11 ; C. +,12, + ; P. 10 ; 

 V. I, 1. 



Color. — General color dull silvery, minutely punctulated with black ; 

 upper half of body with large irregular areas of black ; chin, throat, and 

 abdomen black in males, silvery in the females studied. Mlsson records 

 a similar condition in G. pungitiiis.* 



The relations of Gasterosteus jmngitius var. hrachypoda to the pungitkis 

 {=Pi/gosteus occidentalis (C. & V.) Brevoort) of New England are shown 

 in the table of comparative measurements which follows. I do not use 

 the name Pygosteus occidetitalis, for the reason that our many-spined 

 stickleback bearing that name shows no characters by which it may be 

 separated from the Gasterosteus pungitius of Linne as a species, and the 

 genus Fygosteus has nothing to exclude it from Gasterosteus. The genus 

 Pygosteus, although credited to Brevoort, was not defined by him ; it 

 appears in Gill's Catalogue t as a name only. The first to indicate 

 characters by which it was thought the genus could be distinguished 

 was Jbrdan; they are stated to be the following : "Dorsal spines 7 or 

 more ; sides mailed or not." | So far as the squamation is concerned, 

 the collections of the United States National Museum show all sorts of 

 individual variation, and justify the ground taken by Giinther in his 

 arrangement of the varieties of G. aculeatus; certainly, the squamation 

 is not even of specific importance. The number of dorsal spines in the 

 specimens of G. pungitius studied ranges from 7 to 11. In Gasterosteus 

 inconstans, § Kirtland, the range is from 3 to 6. I have seen a fresh- 



* " Variat aMomine nigro." — Prod. Ichth. Scand., 1832, p. 86. 



t Catalogue of tlie Fishes of the Eastern Coast of North America from Greenland to 

 Georgia, by Theodore Gill, Jan. 1861, p. 39. 



t Manual of the Vertebrates of the Northern United States, 1876, p. 248. 



$ Eucalia inconstans, Jordan, Manual of Vertebrates, 1876 ; Proc. Acad. Nat. Sci. Phila., 

 1877, p. 65. The generic characters ascribed to Eucalia are: (1) "Dorsal spines iu a 

 right line," which is also true in Gasterosteus aculeatus, L. ; even in the many-spined 

 stickleback, G. pungitius, I have frequently seen the last four or fiva spines in a right 

 line, while the anterior ones preserved their zigzag arrangement ; (2) " Ventral plates 

 coalesced into a narrow plate on the median line between the ventral fins," just as in 

 G. aculeatus and G. jnuigitius ; (3) "A distinct sub-quadrate post-pectoral plate," which 

 is present in most sticklebacks ; the " associated characters " indicated contain nothing 

 generically distinctive. 



