DESCRIPTION OP GENERA AND SPECIES. 285 



Cornulites sp. undt. (plate 26, fig. i). 



A single imperfect specimen of an annelid tube, apparently a member of the 

 genus Cornulites, occurs in the collection. Its diameter is 2.5 mm., and the speci- 

 men as preserved is about 13 mm. long, the sides tapering very slightly in this 

 length. The shell is marked by annular ridges about i mm. apart and by much 

 finer annular striae which cover both the elevated annular ridges and the depressions. 



Gastropod gen. and sp. undt. 



A few fragments of gastropod shells occur in the collection, too imperfect for 

 generic determination. All the specimens are apparently portions of flat-coiled 

 species and none of them could have been more than 15 mm. in diameter. 



Cyrtodonta ? sp. undt. (plate 26, fig. 2). 



A single pelecypod shell occurs in the collection, too incomplete for identifica- 

 tion, although it seems to have something of the form of some of the American spe- 

 cies of Cyriodonia. The dimensions of the specimen can not be accurately deter- 

 mined, but its length was apparently about 15 mm. and its height about 13 mm. 

 The surface is marked by rather conspicuous lines of growth and by much finer 

 radiating lines. 



Vaginoceras sp. undt. 



Several fragmentary specimens of the invaginating cones of the siphuncle of a 

 member of this genus are present in the collection. The maximum diameter of the 

 specimens preserved is 13 mm. 



Ampyx chinensis Weller (plate 26, fig. 16). 



1907. Ampyx chinensis Weller, Proc. U. S. Nat. Mus., vol. xxxii, p. 559. 



Cranidium subsemicircular in outline, width 6.8 mm., length 3.5 mm. Gla- 

 bella prominent, produced anteriorly somewhat beyond the frontal margin, sub- 

 angular along the dorsal median line, the sides convex and sloping rather abruptly 

 to the dorsal furrows ; at the anterior termination of the glabella is the fractured base 

 of a slender cylindrical spine whose length can not be determined ; lateral furrows 

 obsolete. Occipital furrows narrow and shallow. Occipital segment very short. 

 The fixed cheeks are broad, convex, and subtriangular in outline, marked by post- 

 marginal furrows which continue from the extremities of the occipital furrow. 



This species is a close ally of A. nasutus Dalman, but it differs from all illustra- 

 tions of that species in its proportionately greater width. The free cheeks, thorax, 

 and pygidium have not been observed, the species being founded upon a single, 

 nearly perfect cranidium. 



Ampyx sp. cf. A. costatus Boeck. 



Two fragmentary specimens of the cranidia of a larger species of Am pyx than 

 that last described occur in the collection. So far as they are preserved they 

 resemble the illustrations oiA. costatus given by Schmidt, 1 but they are too incom- 

 plete for certain identification. 



Bathyurus sp. undt. (plate 26, figs. 17, 18). 



A minute trilobite cranidium 2 mm. in length is apparently a member of the 

 genus Bathyurus. The glabella is smooth, strongly convex, with the two pairs of 

 lateral furrows almost obsolete. The occipital segment is rather broad and is appar- 

 ently smooth; the cheeks have been almost entirely destroyed. 



'Rev. Ostbalt, Sil. Tril., pt. 4, plate 6, figs. 24, 25. 



