132 BULLETIN OF THE 



Cardium medium Lnrara. 



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

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



Cardium sp. indet. 



Sigsbee, off Havana, in 182 mis., dredged several young valves remarkably 

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

 five, with their interspaces, cover nearly half of the shell in its middle part. I 

 cannot identify them with any species figured in the Icoiuca, 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 exquisitely stained with lemon-yellow, orange, and carmine, 

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

 lated; outer surface of tbe 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 

 squares ; the concentric ridges are occasionally a little irregular or diehotomous, 

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

 in the region immediately in front of the beaks the radiating ribleta 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 

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

 barred across with thin lamella? at regular intervals, which lamelhr are 

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

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

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

 in the most perfect spei imens ; anterior <<\^v and basal margin rounded ; pos- 

 terior extreme of the hinge-line .-lightly angnlating the curve of the posterior 



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

 cent\filotutn Cpr. and C Richariaonii Whin 



