NO. 1312. SYNOPSIS OF THE VENERIDM—DALL. 389 



row of spines is wanting- and the outer row abortive. Dione hrevl- 

 ,s2)in<(ta and 1). hrevisj^ina Dcsliayes, 1858, are variants of this name. 

 Call'iHta longispina Morch, is doubtless a mutation of this species. 



PITARIA (HYSTEROCONCHA) ROSEA Broderip and Sowerby, 1829. 



Gulf of California to Panama. 



Reddish brown, flattish, with only hints of spines, which lie in a 

 white streak radiating from the umbo. Cytherea lej^lda Chenu, 1847, 

 is synonymous. 



PITARIA (LAMELLICONCHA) CONCINNA Sowerby, 1835. 



Magdalena Bay, Pacific coast of Lower California, to the Gulf of 

 California, southward to Panama Bay, the coast of Ecuador and Payta, 

 Peru. 



Donaciform or even rostrate, with concentric round-edged ribs, 

 white, with radial streaks of brown; all brown; or all white. 



Cytherea affinis Broderip, 1835, and Venus paytensis Orbigny, 1847, 

 are synonymous. 



C, tortuom Broderip, 1835, is a white specimen with the ribs more 

 irregular than usual. According to Romer, C. suppositrix Menke, 

 1849, may be this species. 



PITRARIA (LAMELLICONCHA) CIRCINATA Born, var. ALTERNATA 



Broderip, 1835. 



Gulf of California to Payta, Peru. 



When fully developed this is larger, more convex, and with more 

 distant concentric ribs than any Atlantic specimens I have seen. 

 Immature specimens are often hardly distinguishable. For synonymy 

 see Atlantic list. 



The original alt&rnata of Broderip was founded on two shells, per- 

 haps distinct from each other. The description was taken from one 

 and the suggestion of the name from the other, which last is repre- 

 sented by Reeve's figure 28J, in the Iconica, 1863. Those writers who 

 have had an opportunity to examine Broderip's types agree in refer- 

 ring them to P. circinata as a variety; from the figures I should sup- 

 pose them to be closer to P. concmna. Romer, in 1868, figures the 

 second or white form with alternating ribs (pi. xxxvi, fig. 2), whicii 

 is more like P. circinata than the other. 



PITARIA (LAMELLICONCHA) CALLICOMATA Dall, 1902. 



Ba}" of Panama, in 7 to 30 fathoms. 



White and rather earthy, with primary concentric himelUv, from 

 one to three secondary smaller lamella^ intervening between each two 

 primaries. It is more elongate, with a longer and narrower lunule 

 than circinata and more oval than alternata. 



