dall: mollusca and bkachiopoda. 395 



mud, bottom temperature 46°. 9 F. U. S. N. Mus. 118,241; and station 2783, 

 iu 122 fathoms, mud, temperature 4ij°. 



This species, agreeing exactly witli the figure ia the report of the Mission to 

 Cape Horn, above cited, has a pale brownish periostracuni with rather short hairs, 

 prominent though small beaks, and smooth flat valve-margins. The periostracuni 

 is less adiiereut than usual in this genus and oflcn has dropped off entirely in 

 comparatively fresh specimens. The iiairs are mucli longer in the young than in 

 the average adult. The area is very narrow ; the ligament occupies a very narrow, 

 lozenge-sliaped area about equally in front and behind the beaks ; the resilium ia 

 central, forming a minute triangle in each valve, and the depression in the amphi- 

 detic area to receive it is very shallow and sometimes, in a slightly eroded valve, 

 imperceptible, which accounts for the error already alluded to. Another error, 

 probably typographical, occurs in printing the measurements, as will be seen on 

 comparing them with the figure. The average measurements are : length, 26 ; 

 height, 24; diam. 9 mm., exclusive of the periostracuni. 



The sculpture consists of feeble, irregular incremental lines and obsolete numer- 

 ous, rather distant radial striae, out of which the hairs grow, the interspaces being 

 quite flat, and the striae, broken by the lines of growth, have here and there a 

 faintly punctate aspect. There are ten anterior and about the same number of 

 posterior teeth, sometimes forming a continuous arch, but usually with a faint 

 medial depression, more conspicuous iu the young shells. 



Nothing corresponding to the unfigured L. hirtella Mabille ct Rochebrune, 

 from Orange Harbor, was discovered in the " Albatross " collections. 



(B. With crenulate Margins.) 

 Limopsis diegensis Dall, n. sp. 



Plnte 15, flgurcs 13, 15. 



This small, oblique-ovate, and rather swollen species is light brown, rather 

 sparsely pilose, thin, with a small resilium, about seven anterior and four to five 

 posterior hinge teeth, which are small and delicate, the two series separated by a 

 short edentulous gap. When the periostracum is removed, the sculpture is not 

 unlike that of //• jousnecnimi, but more empliatic, and the radii are distinctly punc- 

 tate. The interior is faintly grooved and the ventral margin distinctly crenulate, 

 or rather beaded. 



Off San Diego, in 80 fathoms, F. W. Kelscy ; U. S. S. "Albatross," station 

 2923, in 822 fathoms, mud, off San Diego, California, bottom temperature 39° F. 

 U. S. N. Mus. 122,585. 



Limopsis mabilliana Dall, n. ep. 



Shell small, subquadrate, with pale brown periostracuni sparsely arranged along 

 t!ie radial and concentric sculpture so as to form a fringed reticulum, the hairs 



I 



