NEW ANTILLEAX MOLLUSKS REHDER 195 



wavy, spiral striatum; the axial ribs are obscurely nodulose at the 

 angulated shoulder of the whorls, which becomes obscure towards the 

 last whorl, the axial ribs tending to evanesce near the periphery. 

 Anal fasciole broad, surrounding a very minute umbilical chink. 



The type. U.S.N.M. No. 411896, measures: Height, 10.8 mm.; 

 breadth. 5.3 mm. It was dredged by John B. Henderson, Jr., in 40 

 fathoms off Ajax Reef. Fla. We possess this species also from 

 Miami to Conch Reef, and Frank Lyman has lately dredged it in 

 18-35 fathoms off Yamato between West Palm Beach and Fort 

 Lauderdale, Fla. 



This shell is broader than the other recent Crepitacellas, i. e., 

 gabbi Dall, columbella Dall, and leueophlegma Dall (described as a 

 Daphnella) , and less strongly shouldered and axially sculptured than 

 gabbi Dall. C. leueophlegma is not angulate at the shoulder. 

 Dolopham s Gabb, 1872. is a synonym of Grepitaeella. 



Genus PERISTICHIA Dail, 1889 



PERISTICHIA AGRIA Dall 



Plate 20, Figure 4 



18S9. Peristichia agria Dall, Bull. Mus. Comp. Zooi., vol. IS, p. 340. 



This species has never before been figured, and in lieu of a figure 

 of the type, which is at present unavailable, I have used a specimen 

 collected by Dr. B. R. Bales on Bonefish Key, Fla.; it has also been 

 collected on Key Vaca. 



Originally proposed as a genus of dubious affinities, Dall later 

 placed Peristichia in the Pyramidellidae near Oscilla. Bartsch 

 (Proc. Biol. Soc. Washington, vol. 17. p. 9, Feb. 5, 1904) considered 

 it a subgenus of TurbonHla. Thiele, 1929, does not mention it at 

 all, and Wenz (Handb. PalaozooL, vol. 6, p. 874, 1940) lists it as a 

 subgenus of TurbonHla with a question. An examination shows that 

 it is a pyramidellid close to Triptychus and should be accorded full 

 generic rank. It differs from Triptychus in having only one basal 

 entrant spiral cord, instead of two, and in lacking columellar folds. 



Besides P. agria and the type of the genus, P. to ret a Dall, the only 

 other known species is Ividella pedroana Dall and Bartsch, 1909, 

 from southern California, P. agria differing from it in being more 

 slender, white instead of cinnamon, and with more delicate sculpture. 



The West Atlantic form commonly listed as Oscilla biseriata Gabb 

 or nivea Morch should be known as Triptychus niveus Morch, 1875. 

 Oscilla is a distantly related Japanese group, while biseriata Gabb is 

 a probably related species of Triptychus from the Pliocene of Costa 

 Rica. The description of this species, by the way, was published in 

 1881, not 1874 as given in Johnson's list 



