408 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



margin from the umbones and increasing in strength backward; be- 

 hind the last and strongest an excavated concentrically striated space 

 marks the beginning of the rostrum which beyond that has four or five 

 faint radial threads and is abruptly trimcate. Length 8.9; height, 5; 

 diameter, 3.2 mm. Cat. No. 208650, U.S.N.M. 



Station 2911, on the edge of Cortez Bank, in 60 fathoms. 



CALYPTOGENA ELONGATA, new species. 



Shell resembling a Tagelus in form, elongate compressed, white 

 mider a yellowish periostracum, rounded at both ends, base nearly 

 straight; anterior dorsal slope short, beaks low, small, pointed, about 

 10 mm. from the anterior end of the valves, posterior slope long, gently 

 arcuate; surface devoid of any sculpture except rather conspicuous 

 incremental lines; ligament strong; interior porcellanous white, 

 paUial line entire; hinge teeth smaD, normal. Length, 44; height, 

 17.5; diameter, 10 mm. Cat. No. 110774, U.S.N.M. 



Off Point Loma, California, in 275 fathoms, at station 4432. 



This can be distinguished at once from the C. pacijica by its elongate 

 form and more delicate and compressed shell. 



MIODONTISCUS MERIDIONALIS. new species. 



Shell small, solid, white, with 9 or 10 strong rounded adjacent 

 radial ribs cut by about as many concentric incised lines, the segments 

 of the ribs more or less swollen ; beaks small, erect, no visible lunule, 

 or escutcheon; teeth strong; inner basal margin coarsely crenulate. 

 Length, 4; height, 4; diameter, 2 mm. Cat. No. 208948, U.S.N.M. 



Station 4309, off Point Loma, California, in 78 fathoms. 



Smaller, less compressed, and more conspicuously sculptured than 

 the northern M. prolongatus. 



MILNERIA KELSEYI, new species. 



This species has been confused from the beginning with M. minima 

 Dall, and is best diagnosed comparatively. The latter has the radial 

 sculpture, especially the four strong ribs of the posterior part, coarsely 

 and conspicuously imbricated, with no very marked keel from the 

 umbo to the posterior basal angle. The shell in a general way is in 

 all respects less angular. M. Icelseyi has a conspicuous ridge extend- 

 ing from the umbo to the posterior basal angle; the imbricated ribs 

 are less conspicuous, the scales smaller and less prominent, the an- 

 terior end more attenuated, the shell wider and more depressed, and 

 is apparently larger when mature. Length, 11; height, 3; diameter, 

 4.5 mm. Cat. No. 253037, U.S.N.M. 



On Haliotis shells. Central California. 



M. minima has a rather large conspicuous impressed lunule and 

 smaller narrow escutcheon; M. Icelseyi an extremely small lunule and 

 an escutcheon larger and more conspicuous. 



