498 Dr. F. Haas on new 



inflated, rounded in front and nearly vertically truncated 

 behind. Posterior ridge high, distinctly angulated. Basal 

 margin straight or slightly curved. Beaks somewhat promi- 

 nent, situated at ^ of the total length ; their sculpture 

 consists of concentrical, undulated ridges, covering about one- 

 half of the disk, and running upwards and backwards across 

 the posterior slope. Epidermis of a yellowish green, shining. 

 Hinge consisting of two cardinals and two laterals in the lett, 

 one cardinal and one lateral in the right valve. The cardinals 

 are solid, lamellated, that of the right valve accompanied in 

 front by a very low lamellar auxiliary tooth. Laterals long, 

 straight. Interval short, broad, not distinctly separated from 

 the cardinal teeth. Anterior cicatrices distinct, deep ; poste- 

 rior distinct, faint. Dorsal cicatrices united to a groove 

 situated at the inner side of the interval. Beak-cavities 

 shallow. Nacre silvery, brilliant. 



Length 43, height 25, diam. 16 mm. 



Hah. Pisui, Hainan. Collected by Mr. Schode. 



Two specimens in the Senckenberg Museum ; five speci- 

 mens, including the type, in the Berlin Museum. 



4. Ptyclwrhynchus Icevis, sp. n. 



Shell elongate-elliptical, subsolid, rather compressed, 

 rounded in front, bluntly pointed behind about the middle of 

 the height. Posterior ridge low, rounded angulate, basal 

 margin regularly curved. Beaks somewhat prominent, 

 situated at -^fy of the total length ; their sculpture is invisible 

 on account of erosion. Epidermis smooth, shining, of a 

 blackish brown, with darker lines of growth. Hinge con- 

 sisting of two cardinals and vestiges of two laterals in the 

 left, one cardinal and vestiges of one lateral in the right valve. 

 Cardinals high, the one of the right valve pyramidal, the 

 anterior one of the left valve smaller and lower than the 

 posterior one almost triangular. Laterals very short, low, 

 only indicated, interval long, narrow and smooth. Anterior 

 cicatrices deep, rough, that of the anterior adductor and that 

 of the anterior retractor confluent. Posterior cicatrices 

 distinct, faint. Dorsal cicatrices united to a narrow groove 

 situated at the inner side of the interval. Beak- cavities 

 shallow. Nacre reddish, bluish at the margin, not brilliant. 



Length 59, height 31, diam. 16 mm. 



llab. iSaghalin Island. Collected by Admiral Keppel. 



Two specimens in the Senckenberg Museum, presented by 

 Messrs. Sowerby and Pulton. 



