Explanation of Plate 11 



Figs. 1-3. — Burcuium angulosum var. normale Dall: 1, a typical \ar. normale, from .i7 fct-t 

 (May 30, 1950), showing the smooth whorls with very weak axial folds only near the 

 suture; 2, from 37 feet (May 17, 1950), showing slighth' stronger axial folds; 3, from lil 

 feet (Mar. 10, 1950), showing a faint carina and, on the last whorl, a.xial ridges resulting 

 from growth difficulties. 



Figs. 4-6. — Buccinum angulosum var. subcostatum Dall: 4, a specimen with somewhat less 

 pronounced longitudinal ribs than typical; 5, a typical var. subcostatum; 6, a specimen 

 with strong longitudinal ribs and with a faint spiral cord. All from }7 feet (Ma}- 17, 

 1950). 



Fig. 7. — Buccinum angulosum Gra\', a typical \'oung adult from 64 feet (Ma}' 17, 1950). 

 (For mature adult, see pi. 17, fig. 5.) 



Figs. 8-10. — Buccinum angulosum varieties: 8, a specimen from 37 feet (Ma}- 17, 1950), 

 showing characteristics of var. normale (fairly smooth body whorl), var. subcostatum 

 (stronger axial folds than in var. normale), and var. transliratum (a spiral cord); 9, a 

 specimen from 64 feet (May 17, 1950), showing less of the characteristics of var. normale 

 and more of those of var. subcostatum and var. transliratum (stronger axial ribs, more 

 and stronger spiral cords than in 8). 10, a specimen washed ashore (September 1949), 

 strongly resembling var. subcostatum but with spiral cords suggestive of var. transliratum. 



Figs. 11-13. — Buccinum angulosum var. transliratum Dall: 11, a specimen from }! feet 

 (Ma}' 17, 1950) with three cords but with weak axial folds or ribs on last whorl; 12, a 

 form from 17 feet (May 26, 1950), with strong axial ribs, two strong and one faint cord 

 on the last whorl; 13, a form intermediate between \ar. subcostatum and \ar. trans- 

 liratum washed ashore (September 1949). 



Magnification: All X .64. 



