438 BULLETIN OF THE 



facts is erroneous. In any case, the mere attitude of the laminae of the cte- 

 nidium can have but very slight systematic importance. 



Amusium pleuronectes (I. p. 209). The form referied to as this species 

 dredged in the Gulf of Mexico, proves by comparison with the Pliocene fossils 

 to be Amusium Mortoni Say. In specimens of equal size it can hardly be 

 distinguished from that variety of Amusium pleuronectes which has the in- 

 ternal lirse paired, but the A. Mortoni grows to a larger size, is then rather 

 more circular and slightly more convex than any of the Oriental forms, and 

 l'.)r jDractical purposes may be regarded as a distinct species. 



Pecten phrygium (I. p. 217). See Plate XL., Fig. 1, Part II., where 

 this species is figured, and also in Agassiz, Three Cruises of the Blake, II. 

 p. 72, Fig. 299. A fine flattened pink and white rayed Pecten, with 30 in- 

 ternal liijTc arranged in pairs and about 15 ribs, was dredged in 124 fathoms, 

 off Cape Hatteras, by the U. S. Fish Commission, at Station 2602. It will be 

 fully described and figured in the Report on the Voyage of the Albatross, under 

 the name of Pecten Tryoni. Another small Pseudamusium (strigillaturn n. s.), 

 characterized by much elevated crowded concentric lamellae on both valves, 

 inflated and white, has been added to the fauna of the Antilles and Florida 

 Reefs by Dr. Rush and the Albatross party. It is only about 10.0 mm. in 

 height, but P. Tryoni measures over 60 mm. in height, and as much in 

 width, and has much the oblique form of P. j)liry(jium. 



Leda acuta, Conrad (I. p. 251). An examination of Dr. Gould's type of 

 Leda unca in the Gould collection at Albany, New York, shows that, in spite 

 of the discrepancy between his description and the characters of L. acuta, his 

 name is merely a synonym of acuta. Gould's type is a typical specimen of 

 L, acuta. 



Malletia (Tindaria) cytherea, Dall (T. p. 254). The shell described in 

 the first paragraph on page 255 (Part I.) proves to be distinct from my origi- 

 nal M. cytherea, and is figured here as Malletia amahilis Dall, Plate XL. 

 Fig. 8. The original M. cytherea never attains the size of M. amahilis, and is 

 of a squarer, less inflated, more Cytherea-\\\iQ, form. 



Cryptodon (I. p. 267). A large specimen of Cryptodon which has since 

 been received (about 17.0 mm. high) affords the following notes as to the soft 

 parts. The foot is extremely slender (0.5 mm.) with a small spindle-shaped 

 dilation at the distal end, circularly rugose, and about 40.0 mm. long, as con- 

 tracted in alcohol. The gills are as long as the shell, or nearly so; the stem has 

 a dorsal and a ventral lamina, and the dorsal lamina is reflected outward and 

 downward, until its lower margin is on a level with the stem. There is only 

 one pallial and branchial opening, with the edges posteriorly thickened or 

 infolded but nearly smooth. The anal opening has no tube, but forms a sim- 

 ple long-ovate slit. The gills are free, except proximally, over two thirds of 

 the whole length being unattached. The mouth is small, with a narrow raised 

 edge like a Polyzoon epistome, but no palpi. The ovarian and hepatic lobules 



