50 



BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



Descnption. — Test planospiral, of few coils, completely involute, 

 compressed, periphery acute or very slightly rounded, somewhat 

 lobulated; chambers distinct, few in number, three to five in the 

 last-formed coil, the last in adults occasionally assuming peculiar 

 forms, high, biconvex, sutures clearly marked but not greatly exca- 

 vated; wall thin, of fine sand grains with an abundance of cement, 

 smooth and polislied; aperture an elongate, nearly straight, narrow 

 slit, somewhat above the base of the chamber and usually in a slight 

 depression; color a yellowish or reddisli brown. 



Diameter, up to 2.2 mm. 



DiMribution. — While this species has a wide distribution it is 

 usually found in deep cold waters and usually is rare. In the 

 Atlantic it has been found as far, north as Davis Strait (Norman) 

 and from several Challenger stations in the deeper Atlantic (Brady). 

 Goes records it from the Gulf of Mexico and south of Cuba. Flint's 

 specimens were from the northeastern coast of the United States 

 and from the northern part of the Gulf of Mexico. From the Alba- 

 tross material I have had H. ringens from. 18 stations, mostly in deep 

 water between 37° and 40° N. latitude, and 68° and 73° W. longitude. 

 Five stations are. in the northern part of the Gulf of Mexico and one 

 from the eastern Caribbean. 



The species is a very well marked one and can hardly be confused 

 with any other. Its color, polished surface, general biconvex 

 shape and especially in addition to these the peculiar aperture will 

 distinguish it. The last-formed chamber in adults may be variously 

 shaped as is shown in the figures. On the interior there is often a 

 decidedly lipped condition about the aperture due to the bending 

 in of the walls. 



Hap lophrdg m oidcs ring ens — m a terra I examin ed. 



