300 PROCEEDINGS OF THE NATIONAL MUSEUM. voi..xxni. 



Rec'luz, 1852 {TeUhui lacnjiiKihiDKla Deshayes), but after long- study I 

 .think the two aspects can not ))e specifically separated. The sinus is 

 al)out half confluent Ijelow. It has been named Tellina rechiziana hy 

 Tryon in 1869, on account of the existence of TelliTm souleyetl Hanley, 

 1811. I have no dou})t that the original Psammobia lusorla Say, 1822, 

 was based on a large si>ecinien of this species, but it can not be recog- 

 nized from Say's description and Conrad's figure. 



MACOMA (CYMATOICA) ORIENTALIS Dall, 1889. 



Florida Straits, south to Santo Domingo. 



This appears to be distinct from, though allied to, the West Indian 



Macoina ( Cymatoica) arcuata Sowerb}', 1867. 



Subgenus Psammacoma Dall. 



MACOMA (PSAMMACOMA) TAGELIFORMIS Dall, 1900. 



Texas. 



Two closely allied species appear to have l)een generally confounded 

 under the name of hrevifrons. That to which the name tagelifm'mis 

 is assigned here reaches a length of 15 mm., and has the pallial sinus 

 gibbous, short, high, and only slightl}^ confluent below. 



MACOMA (CYDIPPINA) BREVIFRONS Say, 1834. 



New Jersey south to liio Janeiro. 



This diflfers from 2f. tagelifoi'inin in its pale orange flush over the 

 central portion, in its usually nuich smaller size, and in its elongate- 

 oval pallial sinus, extending nearl}" to the anterior adductor and largely 

 confluent below. The Miocene Tellina mrginiana Conrad, 1866, is 

 closely allied. Sa3"'s figure does not agree with his diagnosis and, as 

 it was published aft(n' his death, may represent another species. 



MACOMA (CYDIPPINA) LIMULA Dall, 1895. 



Cape Lookout, North Carolina, south to Barbados. 



Always identifiable by its finely granular surface. The sinus is long 

 and partly confluent. 



Bertin cites a manuscript name, Tell'ma limvla of Valenciennes, in 

 his monograph of 1878, but as this referred to a true Tellina^ while the 

 present species is a 3facoma, the name of the latter need not be 

 changed. 



MACOMA (CYDIPPINA) EXTENUATA Dall, 1900. 



Between the Mississippi delta and Cedar Keys, Florida, in 32 

 fathoms, sand. 



Elongated and with a dull surface, the sinus long and partly con- 



