1905.] NATURAL SCIENCES OF PHILADELPHIA. 119 



This delicately colored clam is remarkably handsome for so northern 

 a species. It has some resemblance to Macrocallista pacifica (Dillw.), a 

 species better known as Meretrix (or Callista) chinensis Chemn., but 

 that species is smaller, more oblong and smoother, and it is more or 

 less marked with purple. 



A somewhat larger specimen of M. chishimana, measuring length 78, 

 alt. 57, diam. 32.5 mm., was contained in a collection of shells of 

 unknown locality, but all species of Yesso and northward, which has 

 been in the Academy many years. 



Dr. William H. Dall has shown that the well-known and appropriate 

 name Callista cannot be used for this Venerid group, but I believe no 

 one has noticed that it was originally based upon the single species 

 Madra neapolitana Poli {Test. utr. Sicil, I, pp. 67 and xi, 1791). In 

 a later volume Poli added several species of Veneridce; but subsequent 

 additions do not affect a name based upon a single species. Callista 

 Poli i^ therefore a synonym of Madra s. str. 

 Lithophaga lithura n. sp. PL V, figs. 37, S8, 39. 



The shell is thin, cylindrical, brown, and sculptured with growth- 

 lines only under a smooth, thin, gray-white calcareous layer, which 

 almost completely envelopes it. The low beaks are very near the 

 anterior end. The hinge-margin is but little raised, hardly modifying 

 the cylindric contour, but the height of the shell diminishes slightly 

 toward both ends. The anterior end is narrowly rounded, the pos- 

 terior end abruptly and squarely truncate. The calcareous layer thick- 

 ened at the posterior end, where it projects, is abruptly narrowed, and 

 is excavated on the inner faces, and continued in narrow posterior projec- 

 tions. The valves arc flesh-tinted within, becoming blackish-purple 

 at the posterior end . 



Length 37, alt. 12, diam. 9.5 mm. 



Length 32.5, alt. 10, diam. 8.5 mm. 



Kikaigashima, Osumi. Types No. 88,294, A. N. S. P., from No. 

 1,577 of Mr. Hirase's collection. 



This species is remarkable for the posterior truncation of the valves, 

 and their mucronate, internally excavated, stony tails. 

 Trapezium japonicum u- sp. PI. V, figs. 34, 35, 36. 



The shell is rather solid, oblong, the altitude nearly half the length, 

 the beaks at the anterior sixth or seventh of the length. Surface dull 

 and earthy, whitish with some red or livid stains, and roughened by 

 growth-wrinkles which are most strongly marked posteriorly. Only 

 small remnants of a thin cuticle remain near the ventral margin. Dorsal 



