From the Niagara Formation. 



73 



gination for the reception of the median extension of the opposite 

 valve. 



Surface marked by fine sublamellose striae of growth, which are 

 distinctly curved backward on the prominent parts of the shell and 

 forward in the depressions. 



This form so nearly resembles Pentamerus fornicatus of the Clin- 

 ton limestone that I can only regard it as a variety of that species. 



LAMELLIBRANCHIATA. 



GONIOPHOKUS SPECIOSUS U. Sp. 



Shell subrhomboidal, a little more than twice as long as wide ; 

 hinge-line two-thirds the length of the shell ; anterior extremity 

 somewhat obliquely truncated ; a prominent angulation extending 

 from the beak to the posterior basal margin. Surface marked by 

 striae of growth which are parallel to the margins of the shell, 

 being gently curved below the carination, and above it turning 

 forward parallel to the truncate posterior margin. Length of 

 specimen eighteen mm. 



GASTEROPODA. 



LOXONEMA ? 



Compare Loxonema Leda. Hall. 20th Rep. St. Mus. Nat. Hist., p. 346. 1887. 



. Several specimens referred to this genus have been obsci vcd, con- 

 sisting entirely of casts of the interior. They do not possess suf- 

 ficiently well defined characters to designate them as a species or 

 to refer them to any described form. 



PTEROPODA. 



CONULAEIA INFREQUEXS U. Sp. 



Cone strong, marked by prominent transverse ridges, with inter- 

 mediate furrows which are gently curved; ridges crossed by 

 numerous strong nodes, which are slightly elongate in a direction 

 transverse to the ridges, and perceptibly wider at their lower ex- 

 tremities; about ten of these nodes in the space of four millimetres 



Trans, a;.] 10 



