410 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



ERYCINA BAKERI, new species. 



Shell small, white with a pale yellowish periostracum, subquadrate, 

 inequilateral, the anterior end shorter; hinge line short, straight, at 

 the outer extremities usually a small spinule, beaks pointed, the pro- 

 dissoconch visible; from the beak extends a wide depression obliquely 

 backward to the middle of the base, becoming more defined distally; 

 at the base in the adult it is strongly marked and emphasized by a 

 rounded sulcus in the margin, behind which the surface rises into a 

 rounded ridge armed with one or more elevated short lamellae, and 

 having its basal termination produced into a sort of hook; hinge 

 rather feeble, valves rather compressed. Length, 6.3; height, 4.5; 

 diameter, 2 mm. Cat. No. 225192, U.S.N.M. 



Off South Coronado Island, in 3 to 6 fathoms. Dr. F. Baker. 



This remarkable little shell doubtless owes its curious modifica- 

 tions to a commensal habit of living attached to some other animal — a 

 crustacean or annelid. 



ERYCINA BALLIANA, new species. 



Shell small, with the outline of a very compressed Kellia, white with 

 a very pale yellowish periostracum, concentrically microscopically 

 threaded, the threads occasionally becoming microscopically lamellar; 

 valves nearly equilateral, the anterior part shghtly longer, base evenly 

 arcuate, the posterior end somewhat attenuated. Length, 3; height 

 2.9; diameter, 1.7 mm. Cat. No. 225191, U.S.N.M. 



Off South Coronado Island in 3 fathoms. Dr. F. Baker. Named in 

 honor of Mrs. Paula Ball, of the Conchological Club of Los Angeles, 

 California. 



ERYCINA CHACEI, new species. 



Shell small, compressed, rounded-quadrate; nearly equilateral, the 

 anterior end slightly shorter; beaks low, pustular, minute; dorsal 

 margm nearly straight, basal margin gently arcuate; surface fuiely 

 concentrically striate, whitish under a pale ashy periostracum, both 

 ends nearly evenly rounded, hinge very feeble. Length, 5.3; height, 

 3.5; diameter, 1.8 mm. Cat. No. 211219, U.S.N.M. 



Station 4343, off the South Coronado Island, m 155 fathoms. 

 This shell may eventually prove to be a PseudopytMna. Only one 

 right valve was obtained. It is named in honor of Mr. and Mrs. E. P. 

 Chace, of Los Angeles, California. 



ERYCINA SANTAROSAE, new species. 



Shell small, compressed, whitish, with a thin pale brownish dull 

 periostracum; profile approaching E. halliana but more elongated, and 

 the surface smooth, almost pohshed and without the microscopic con- 

 centric sculpture; evenly ovate, nearly equilateral, the anterior end a 



