MUSEUM OF COMPARATIVE ZOOLOGY. 63 



Hastula cinerea Born (+ salleana Deshayes and jamaicensis C. B. Adams), 

 is in the Museum from Corpus Christi, Texas, from Vera Cruz, Carthagena, 

 and the West Indies. 



Subula floridana Dall, has been dredged by the U. S. Fish Commmission 

 near Key West in 45 fms., and in the Straits of Florida in 56 tins., sand. It 

 differs from S. triseriata Gray (Indo-Pacific), which is its nearest relative, in 

 the absence of the peripheral nodules forming the post-sutural series, and of the 

 decussation, beside being less acutely elongated. It reaches a length of 70.0 

 mm. with a width of 10.25 mm. in twenty-six whorls of a pale straw color. 



The species of Acus may be discriminated as follows : — 



A. Whorls concave. 



Both sides of the suture nodulous ; no costae ; spirally grooved ; white. 

 Lon. 19.0, lat. 4.0 mm., whorls 13. Acus concavus Say. 



Post-sutural nodules obsolete ; the grooves replaced by channels separating 

 raised threads ; flexuous obscure costae crossing the less concave whorl ; wine- 

 colored or variegated. Lon. 18.0, lat. 3.5 mm., whorls 12. A. concavus var. 

 vinosus Dall. 



B. Whorls flat or convex. 



a. Shell large, columella keeled. 



Shell coarse, white to dark ash-colored ; strong, straight or slightly flexed, 

 smooth, numerous costae, with their interspaces coarsely threaded or grooved. 

 Lon. 57.0, lat. 11.0 mm., whorls 20. Acus dislocatus Say. 



b. Shell small, acute, elongate, columella not heeled. 



Whorls convex, periphery destitute of nodules, whorls crossed by sharp- 

 edged very flexuous waves ; interspaces with crowded spirals and sharp grooves, 

 which last do not cut the crests of the waves. Ashy to dark purple ; band 

 distinct. Lon. 21.2, lat. 4.7 mm., whorls 15. Acus protextus Conrad. 



Waves etraighter, flatter, fine and numerous, their edges cut by the spiral 

 grooves, sometimes slightly nodulous at the intersections ; band distinct ; color 

 pale brown to dark ashy. Lon. 15.5, lat. 4.0 mm., whorls 13. Acus -protextus 

 var. lutescens Dall. 



Larger; pale yellow with a white pre-sutural area ; the young sculptured 

 like the preceding, the adults with the sutural band nearly obsolete ; costse 

 fine, flexuous, rounded, numerous (26-28), with six to ten prominent primary 

 spirals overriding the costae and with the interspaces finely striate by a secon- 

 dary series of spirals. Lon. 55.0, lat. 10.0 mm., whorls IS. Acus nassulus 

 Dall. 



Smaller; strongly cancellated and nodulous at the intersections; costae about 

 18-20, straight; one faint anterior and three strong spirals between the sutural 

 band and the suture in front; the interstices deep ; band obscure; base more 

 finely reticulated, the spirals stronger than the costse ; color white to pale buff. 

 Lon. 18.0, lat. 3.5 mm., whorls 14. Acus limatidus Dall. 



Larger; early whorls with one row of pointed nodules, later whorls with a 



