no. 2359. AN OPERCULATE SERPULA—WADE. 45 



Outside Distribution. — Monmouth Formation of Maryland; Selrna 

 and Ripley Formations of Mississippi, Alabama; Eutaw Formation 

 of Alabama; Austin Chalk, Texas. 



HAMULUS ANGULATUS, new species. 



Plate 10, figs. 1, 2, 8, 9. 



Description. — Tube small, thick, and strong, but brittle; in form 

 an elongate, gently curved, and often slightly spiral cone; inner 

 shell layer thick, outer layer thin; nucleus unknown; external sur- 

 face marked by six low, sharp, angular, axial ridges; intcraxial 

 spaces broad and gently concave, alternate intcraxial spaces marked 

 by a fine impressed axial line; growth lines obscure on the earlier 

 stages of the shell; interrupted growth lines, irregular and common 

 near the aperture; aperture circular, its margin smooth and thin; 

 internal surface smooth. 



Dimensions. — Imperfect specimen — length, 8 mm.; maximum 

 diameter, 3.5 mm. 



The tubes of this species are brittle and are usually broken. They 

 may be readily distinguished from those of Hamulus onyx Morton 

 by their low, angular axial costae, broad smooth, gently concave 

 interaxial spaces, and by the impressed axial line in alternate inter- 

 axial spaces. 



Occurrence. — Ripley Formation. Dave Weeks place on Coon 

 Creek, McNairy County, Tennessee. 



Collections. — Johns Hopkins University. Yanderbilt University. 

 U. S. National Museum. 



Coty pes. —Cat. No. 32459, U.S.N ,M. 



HAMULUS SQUAMOSUS Gabb. 



Plate 10, figs. 6, 7. 



Hamulus squomomis Gabb, 1859, Cat. Inv. Foss. Cret. Form. U. S., p. 1; I860, 

 Journ. Acad. Nat. Sci., Pliila., per. 2, vol. 4, p. 398, pi. 68, fig. 45.— Stephenson, 

 1914, U. S. Geol. Surv. Prof. Paper 81, p. 24, tabte 2, S. 



Description. — ■" Elongated, curved at the narrow end into a hook 

 sometimes with as much as three-fourths of a whorl, all in the same 

 plane; mouth slightly constricted, nearly circular, edge thin; surface 

 marked by two or three wrinkled longitudinal folds on each side 

 and a heavy squamose plate, very irregular in (he plane of the 

 curve on each side." 



Dimensions. — "Length about 1 inch exclusive of the curve; 

 greatest width of the plates 0.4 inch, diameter of mouth 0.12 inch." 

 Gabb, 1860. 



This species is closely related to Hamulus onyx Morton, but may 

 be readily distinguished by the broad wing-like appendages on the 

 first and fourth axial costae. Hamulus squamosum Gabb is evi- 

 dently a mud-loving form since it is extremely rare in the Coon 

 Creek beds and common in the Selma clay. 



