97« 



PALEONTOLOGY OF NEW-YORK. 



TftEMATOSPIBA MULTISTBIATA. 



^^^^ 



FiOB. 1 & 2. Ventral and front Tlews. 



Fio. 8. The interior of a rentral valve filled with stony matter, and ground so as to show the spires 



Fio. 4. Tbehatospira perforata. The upper part of the shell enlarged, showing boak of ventral 

 valve, perforation and triangular space below. 



Fios. 5 & 6. Trematospiba costata. Dorsal and front views of a specimen. 



Genus Rhynchospira (Hall). 



In the third volume of the PalsBontology of New- York (page 213), I 

 suggested this name as a subgenus of Trematospiba ; but subsequently, 

 from certain peculiarities of hinge-structure, general form, etc., I was 

 induced to propose it as a distinct genus. Although approaching the 

 typical species of Retzia, I am not satisfied of the identity of the two ; 

 and until we have better information regarding the latter genus, I pro- 

 pose to place under Rhynchospira those forms which are similar to R. 

 formosa of the Lower Helderburg group.* 



Rhynchospira lepida. 



PLATE XLV. 

 Rhynchotpira lepida : Hall, Thirteenth Report on the State Cabinet, p. 83. 1860. 



Shell small, broadly suboval, with the valves subequally convex, and 

 the beak of the ventral valve extended. 



•In the Sixteenth Report upon the Slate Cabinet of Natural History, pp. 53-59, 1 havo discu.sscd 

 the relations of Retzia, Tbeuatospiba, RuvxcnospiRA, with the materials at that time accessible 

 to me. 



