BALL: MOLLUSCA AND BRACHIOPODA. 381 



52' S.), in 348 fathoms, mud, bottom temperature 50° F. U. S. N. Mus. 

 90,923. Also at station 2782, iu 258 fatlioms, mud, temperature, 48° F. 



This pretty little species looks something like tlie young of F. thraciaeformis 

 (cf. Hanley, Mon. Nuculacea, fig. 4), but is entirely unlike any species reported 

 from the region mentioned. 



Yoldie (Yoldiella) indolens Dall, n. sp. 



Shell small, tumid, translucent, with a dull olivaceous periostracum, smooth 

 surface aud oval form, except tliat there is a slight angulation near the posterior 

 end of the hinge line ; anterior end shorter, rounded, base evenly arcuate ; pos- 

 terior end sliglitly compressed and augulated above ; interior porcellanous ; 

 hinge-line with about a dozen teeth on each side of a deep, small pit for the 

 resilium directly under the low beak ; pallial sinus distinct but small. Length of 

 shell, 5.25 ; of posterior end, 3.25 ; alt. 3.5 ; max. diam. 2.25 mm. 



U. S. S. " Albatross," station 2784, on the southern coast of Chile, in 194 

 fathoms, mud, bottom temperature 51°.9 F. U. S. N. Mus. 122,740. Also at 

 station 2785, in 122 fathoms, temperature 48° F. 



A comparison of the young of Y. chilenica of the same size with adults of tlie 

 present species shows that, although of very similar profile, in addition to the 

 differences of color aud surface Y. chilenica at that age is much less inflated. 



Yoldia (Yoldiella ?) infrequens Dall, n. sp. 



Shell very small, callistaeform, tumid, inequilateral, covered by an olivaceous 

 periostracum ; beaks prominent, tumid ; both ends of the shell evenly rounded, 

 the posterior not attenuated ; anterior hinge Hue with about nine, posterior with 

 thirteen teeth, separated by a very small pit for the resilium ; interior chalky ; 

 exterior surface evenly, finely, coucentrically striated, the sculpture fainter toward 

 the ends of the shell. Length, 4.4 ; of anterior end, 2.0 ; alt. 3.5 ; max. diam. 

 2.0 mm. 



U. S. S. "Albatross," station 2784, in 194 fathoms, mud, off the coast of 

 southern Chile, bottom temperature 51.°9 F. U. S. N. Mus. 110,092. Also at 

 station 2783, in 122 fathoms, mud, temperature 48°. 



A very simple little species which agrees with no other of the region aud is 

 evidently adult. 



Yoldia (Yoldiella ?) mantana Dall, n. sp. 



Shell small, elongate-oval, white, with a pale yellowish periostracum, nearly 

 equilateral, the beaks o})islhogyrate, showing the protoconch distinctly ; anterior 

 end expanded, evenly rounded; posterior end somewhat attenuated, at the end 

 rounded ; surface with a few irregular concentric striae, but mostly smooth and 



