132 BULLETIN OF THE 



Cardium medium Linne. 



Several valves of a very young Cardium, which may perhaps belong to this 

 species, were obtained by Sigsbee oflf Havana in 80 fathoms. 



Cardium sp. indet. 



Sigsbee, oflF Havana, in 182 fnis., dredged several young valves remarkably 

 elegant in their nodulation and reticulation, having about twenty ribs, of which 

 live, with their interspaces, cover nearlj^ half of the shell in its middle part. I 

 cannot identify them with any species figured in the Iconica, but they are too 

 young to be positive about. 



Cardium (Fulvia) peramabilis n. s. 



Shell having a general resemblance to Fulvia modesta Adams and Reeve,* 

 but smaller, less transverse and much more elegant. Shell generally white, 

 but occasionally exquisitel)^ stained with lemon-yellow, orange, and carmine, 

 inflated, nearly equilateral, valves nearly as long as high, beautifully reticu- 

 lated ; outer surface of the valves divided into two areas with different sculp- 

 ture, the posterior occupying a little more than one third of the surface and 

 separated by a single radiating rib ; anterior region sculptured by about forty- 

 five radiating ribs (three in the space of a millimeter) about equal to their inter- 

 spaces, and reticulated by concentric ridges, strong only in the interspaces, 

 which increase in regular ratio, so that the reticulations form nearly exact 

 S(|uares ; the concentric ridges are occasionally a little irregular or dichotomous, 

 but it does not affect the general very remarkable regularity of the reticulation; 

 in the region immediately in front of the beaks the radiating riblets fail or be- 

 come obsolete and the concentric ones become crowded, wrinkled, and irregular. 

 Over the posterior region the sculpture differs. The bounding rib, which is 

 really composed of two amalgamated riblets, in perfect specimens should bear a 

 delicate crest bent forward and buttressed behind with spurs extending from 

 the interspaces; this, however, is invariably removed by friction, only small 

 portions of it remaining in occasional specimens ; behind this rib the radiating 

 ribs are more slender than in the anterior area, with proportionally wider inter- 

 spaces barred across with thin lamellae at regular intervals, which lamellae aie 

 not continuous with the concentric riblets of the anterior area ; from the inter- 

 spaces project short conical (sometimes grooved and decurved) spurs or spines 

 above the general surface, which are generally mostly removed by friction even 

 in the most perfect specimens ; anterior edge and basal margin rounded ; pos- 

 terior extreme of the hinge-line slightly angulating the curve of the posterior 



* China Seas and Japan, appearing on the northwest coast of America as Cardium 

 centifilosum C'pr. and C Richardsonii Whiteaves. 



