MARYLAND GEOLOGICAL SURVEY 139 



Subgenus ACUS Adams. 



Terebra (Acus) curvilineata Dall. 

 Plate XL, Figs. 3, 4, 5, 6, 7. 



Terebra curvilirata Heilprin, 1887, Proc. Acad. Nat. Sci. Phila., voL xxxix, p. 399. 

 Terebra simplex, small var. Harris, 189S, Amer. Jour. Sci., ser. iii, voL xlv, p. 34. 

 Terebra curvilineata Wliitfleld, 1894, Mou. xxiv, U. S. GeoL Survey, p. 113, pi. xx, 



figs. 14-17. (In part.) 

 Terebra (Acus) curvilineata Dall, 1895, Proc. U. S. Nat. Museum, vol. xviii, p. 36. 

 Not Terebra (Aciis) curvilineata Meek. 



Description. — " Shell acute-conic, solid, with 12 to 14 moderately con- 

 vex whorls; early whorls more flatsided, with numerous narrow, trans- 

 verse, slightly waved riblets extending from suture to suture, with about 

 equal interspaces ; suture very distinct ; sutural band formed by a vaguely 

 limited constriction, not a groove ; a short distance in front of the suture 

 the ends of the ribs thus delimited from the rest have a tendency to 

 coronate the whorl ; on the later whorls the ribs become less regular and 

 somewhat less prominent; aperture longer than wide; outer lip simple; 

 pillar elongated, twisted, smooth ; siphonal fasciole very distinct. Longi- 

 tude, 27; maximum diameter, 9.5 mm. in a specimen of 14 whorls." 

 Dall, 1895. 



The range of variation covered by Dr. Dall's type specimens (which 

 include Whitfield's) and by his description is very considerable and sev- 

 eral varieties may safely be recognized. 



The name " Terebra curvilineata " first appeared as the result of a 

 misprint, being used by Meek in his " Check List " for T. curvilirata 

 Conrad. Whitfield then used the name for the New Jersey forms, igno- 

 rant both that Conrad's name was not " curvilineata " and that his own 

 specimens were not the same as Conrad's. Whitfield's specimens belong 

 to the varieties whitfieldi and dalli as here established. Heilprin had 

 already listed the New Jersey forms as curvilirata Conrad. A year after 

 Whitfield's paper appeared Dall described the species curvilineata as 

 new, basing it upon Whitfield's figured specimens together with material 

 from Greensboro which is here placed in the variety dalli. Associated 

 at Plum Point with the varieties above mentioned is a third, below named 

 calvertensis, which is as closely related to dalli and whitfieldi as they 

 are to each other. 



