26-1 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



KEY TO RECENT SPECIliS OF CHELONIBIA. 



a 1 . Walls heavy, the compartments thick and strong; radii narrow; septa very 



numerous ; living on turtles or on the manatee. 

 ft 1 . Radii rather narrow and well sunken ; cavities in the parietes between 



the basal septa rather deep. 



c 1 . Radii usually notched on the sides, sometimes smooth ; parietes not 

 ribbed or longitudinally folded, the peripheral edge not lobed or in- 

 cised C. testudinarin. 



c 2 . Parietes ribbed or folded, at least near the edge ; radii usually quite 

 without notches. 



d. Parietes with coarse ribs, subdivided near the periphery C. inanati. 



d 2 . Lower part of parietes plicate; periphery lobed C. in. lobatibasis. 



d 3 . Parietes plicate at the edge, showing a few small, loop-like incisions 



in the base C. m. ercnatihnnis. 



b 2 . Radii not developed, or narrow; pa rides xolidly filled itp nearly to tlic 

 base, the septa much interrupted. Shell extremely massive and 



heavy C. carctta. 



a 2 . Thin and light, the outer lamina and septa of the wall very thin, cavities 

 between septa not at all lilled up with calcareous matter. Shell steeply 

 conic, the orifice generally exceeding half the basal diameter; radii broad, 

 smooth, only slightly depressed. Usually living on crabs C. patula 



CHELONIBIA TESTUDINARIA (Linnaeus). 



Plate 62, figs. 1-4. 



1758. Lepas tentudinaria LINN.EUS, Systema Naturae, ed. 10, p. 668. 

 1778. Balaniis polythalainius BOCK, Der Naturforscher 12tes Stuck, p. 170, 



pi. 4, figs. 9a, 9&. 

 1825. Astroh'pas rotund anus J. E. GRAY, Annals of Philosophy, new ser., 



vol. 10, p. 105. 

 . Coronula tcstitudinaria Lamarck, CHENU, Illustr. Couchyl., pi. 2, 



fig. 2. 

 1854. Chelonobia testudinaria Limueus, DAEWIN, Monograph, p. 392, pi. 



14, figs. la-Id, 5 ; pi. 15, fig. 1. 

 1911. Chelonobia teslmlinaria Lhmreus, KKUGER, Die Cirripedien fauna 



Ostasiens, p. 57, figs. 121-125 (mouth-parts of specimens from Sagami 



Bay, Japan). 



Distribution. All tropical and warm temperate seas. Pliocene 

 of Tuscany. 



This species is very widely distributed in tropical and temperate 

 seas, probably \vherever its usual host, the loggerhead turtle, occurs. 

 It is common on our Gulf coast and in the Atlantic as far north as 

 Delaware Bay, but is not often taken farther north. 



The distinct, star-like radii, usually toothed along the edges, and 

 the rather deep excavation of the parietes between the parietal septa 

 will readily separate this species from C. caretta, which must be rare 

 on our eastern coast. The parietes are not folded or ribbed longi- 



