392 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvi. 



CYCLINELLA PRODUCTA Carpenter, 1856. 



Panama Bay, Bridges. 



This .species, represented by a unique valve in the Cumingian col- 

 lection, is said to be produced behind like Cyrena maritima C. B. 

 Adams. 



CYCLINELLA SINGLEYI Ball, 1902. 



Guaymas, on the Gulf of California, and at the delta of the Yaqui 

 River near GuaA'^mas, Singley. 



This is a moderate sized but turgid species with fine, sharp striation, 

 heavy shell, and the posterior adductor scar very large. 



CHIONE (CHIONE) FLUCTIFRAGA Sowerby, 1853. 



San Pedro, California, to the Gulf of California and on the shores 

 of the Gulf. 



The sculpture of the middle of the disk is strong in youth, obsolete 

 or absent in older stages; some large oblique specimens recall in sculp- 

 ture Venus mercenaria. The species is Veiius callom of Sowerby and 

 Deshayes, in 1853, but not Oytherea callosa Conrad, 1837; Diane glh- 

 hosula Deshayes, 1853, and Reeve, 1863, and Venits cortezi (Sloat MS. 

 in) Carpenter, 1864, are synonymous. 



CHIONE (CHIONE) UNDATELLA Sowerby, 1835. 



San Pedro, California, to the Gulf of California and southward to 

 Guayaquil. 



A species larger than but varying like C. cancellata, with many 

 names; a large series of good specimens leaves no doubt as to the con 

 solidations needed. The characteristics are the generally inflated and 

 closely concentrically lamellose form. The young have the lamellse 

 more distant, but they are always thin and sharp. The type is painted 

 with angular brown lines like Venus notata; young specimens with 

 dark brown })lotches are Carpenter's Venus excavata of 1856. Speci- 

 mens without brown painting, adult, and conspicuousl}^ lamellose are 

 V. shnilJhna Sowerby, 1853. The left half of the escutcheon is usually 

 smooth; the right half may be smooth or lamellose. When coarsely 

 lamellose we have the variety neglecta Sowerby, 1839. Carpenter is 

 nuich confused in his synonymy of these species. V. nuttaUll Conrad, 

 1837; V. entobapta Jonas, 181:5; V 2>erdix Valenciennes, 1846; V 

 Ulineqta Reeve, 1863; and V subrostrata Reeve, 1863, not of Lamarck, 

 1818, are synonymous. V. sugillata Reeve, 1863, recalls a young 

 acidulated specimen. 



CHIONE (CHIONE) SUCCINCTA Valenciennes, 1833. 



San Pedro, California, the (iulf of California and south to Panama. 

 This is another variable species, about which Carpenter fell into 



