MARINE MOLLUSKS — MACGINITIE 167 



Astarte montagui (Dilhvyn, 1817) 

 Varieties 



Plate 22, figures 11-16 



Venus compressa Montagu, 1808, suppl., p. 43, pi. 26, fig. 1. [Preoccupied.] 



Venus montagui Dillwyn, 1817, p. 167. 



Nicania banksii Leach, 1819, appendix 2, p. 62. 



Nicania striata Leach, 1819, appendix 2, p. 62. 



Astarte striata J. Gray, 1839, p. 152, pi. 44, fig. 9. 



Astarte banksii J. Gray, 1839, p. 152, pi. 44, fig. 10 (= f. warhami). 



Astarte globosa Moller, 1842a, p. 19.— Reeve, 1855, p. 398, pi. 33, figs. 6a-b. 



Astarte pulchella Jonas, 1845, in Philippi, 1844-1847, p. 60, pi. 1, Astarte, fig. 12. 



Astarte warhami Hancock, 1846, p. 336, pi. 5, figs. 15, 16. 



Astarte fabula Reeve, 1855, p. 398, pi. 33, figs. 5a-b.— Oldroyd, 1924, p. 107, 



pi. 19, figs. 4, 4a.— Morris, 1952, p. 33, pi. 8, fig. 22. 

 Astarte montagui Jensen, 1912, p. 97, pi. 4, figs. 2a-c. 



After Hiatella ardica, and possibly Macoma calcarea, this was the 

 most abundant bivalve collected at Point Barrow. It was taken at 

 depths of 80 to 741 feet. The most important collecting data are 

 given below: 



Three individuals (from 18.2 to 22.5 mm. in length) were dredged 

 from 80 feet (Aug. 21, 1948); 7 (from 18.8 to 24.2 mm.) from 120 feet 

 (Aug. 8, 1949) ; 9 (from 9.3 to 20.7 mm.) from 138 feet; 10 (from 7.7 to 

 20.2 mm.) from 149 feet; 13 (10 from 7.3 to 10.8 and 3 from 16.5 to 

 20.6 mm.) from 162 feet; 7 (from 12.9 to 24.1 mm.) from 204 feet; 12 

 (from 7.4 to 26 mm.) from 216 feet; 38 (from 5.5 to 26.7 mm.) from 217 

 feet; (from 12.1 to 35 mm.) from 246 feet; 12 (from 16.9 to 25.2 mm.) 

 from 295 feet; 32 (from 10.1 to 25.5 mm.) from 341 feet; 25 (from 10.2 

 to 24.4 mm.) from 420 feet; 40 (from 11.9 to 24.4 mm.) from 453 feet; 

 and 8 (from 6.5 to 16.6 mm.) from 741 feet. 



Other material examined : Over 20 specimens (labeled A. Jabula) 

 from localities ranging from Icy Cape to British Columbia. 



Discussion: Jensen (1912) separated the varieties of A. montagui 

 by the statistical method. In his selected types, the height divided by 

 the length in forma typica gave 92.9 percent; in var. striata, 86.7 

 percent; and in var. warhami, 76.1 percent. The breadth divided by 

 the length in forma typica gave 53.6 percent; in the var. striata, 53.3 

 percent; in the var. warhami, 43.2 percent; and in the var. globosa 

 percentages in the 60's. Although the height : length percentages 

 range in the 90's in forma typica, in the 80's in var. striata, and in the 

 70's in var. warhami, there is no sharp dividing line and some shells 

 could as easily be assigned to one variety as to another. Jensen (1912) 

 states ". . . it must be remembered that all possible transitional 

 stages exist between the forms mentioned." 



