Dentaliidae 99 



over the entire surface. Apical notch or sht on convex side, often 

 obHterated. A supplementary tube is present only in young shells. 

 Dredged in four to seven fathoms. 



Dentalium texasiaiium Philippi PI. 20, fig. 129 



Alt. to 30; average 25; diam., 2 mm. Shell more strongly curved 

 posteriorly than in anterior portion. Hexagonal in section except 

 when development of extra ribs result in a somewhat circular and 

 fluted aperture. Dull, dirty white; strong and solid. Six or seven ribs 

 at apex with broad, flat intercostal spaces showing growth lines and 

 intercalated ribs. No apical notch or slit, but usually a supplemen- 

 tary tube. 



Dredged in two to seven fathoms. 



Subgenus ANTALIS Hermannsen, 1846 



Dentalium pilsbryii'i Rehder (£>. pseudohexagonum Henderson) 



PI. 20, fig. 130 



Alt., 28; diam., 2 mm. Gently and evenly curved; section cir- 

 cular, fluted externally; tip not notably slender; white, not polished; 

 nine elevated, rounded ribs with number increased by secondaries, 

 but none are prolonged to the anterior end of shell. Wide, flat 

 intercostal spaces crossed by strong growth lines; no apical notch. 



Dredged in less than one to five fathoms. 



Deiitalium disparilei^- d'Orbigny PI. 20, fig. 131 



Alt., 14 to 28; diam., 2 mm. Regularly and moderately curved 

 throughout its length. Section circular, showing marginal riblets; dull 

 white. Tip slender, hexagonal — the angles extended into six or more 

 narrow primary ribs which separate concave intercostal spaces. 

 There are two broad interspaces with a median rib on the con- 

 cave aspect of shell, and three narrow spaces on the side convexly 

 curved. Some secondary ribbing is present, and there are incon- 

 spicuous growth lines. No notch, but often a supplementary tube. 

 From one to five fathoms. 



1^1 Named for Dr. Henry A. Pilsbry; Gr., pseudes, false. 

 ^^- Lat., dispar, unequal. 



