TITE SESSILE BARNACLES. 289 



edge thin and simple; sheath veiy h)ng, transversely grooved, with- 

 out a distinct lower edge. Operculai- valves long and narrow, thin, 

 the outer layer not deciduous. Basis membranous. 



Type. — StomatolejHis fvcvgustator. 



Station. — In the mucous membrane of the gullet of sea turtles. 



Stomatolepas and Stephanolepas form a little division in the 

 group of turtle barnacles, characterized Ijy the simple, thin basal 

 edges of the compartments, which are without teeth, ribs, or lamina}. 

 The presence of an external shallow median sulcus in each compart- 

 ment shows that their ancestors were Plat ylep as -IW^o, barnacles, since 

 this sulcus is doubtless the vestige of an infolding of the wall. The 

 elaborate sculpture of the exterior of StoTnatolepas seems to be a 

 development of the sculpture of Platylepas., which is formed of con- 

 centric wrinkles cut into beads by radial strije. In Stomatolepas the 

 wrinkles assume an oblique direction and the beads are prolonged 

 to form scalelike processes. 



STOMATOLEPAS ELEGANS (O. G. Costa). 

 Plate 68, figs. 2, 2«. 



1838. Coronnla cJcrians Costa, Di alcimi Balanidi app. al Regno Napoli, 

 1S3S (p. 17 of separate copy), in Atti Accad. Sci. Napoli, vol. 5, 1843, 

 pt. 2. p. 117, pL 1, figs. 1, 2, 8. 



1839. CJiClonibia elegans Costa, Fauna del Regno di Napuli, Cirropt-di, p. 14. 



Distribution. — Taranto, Italy, the host unknown. 



It is described by Costa, as follows : 



Coronnla with the tube conic-truncate, prominent areas bipai'tite, elegantly 

 scrobiculate, the scales coriaceous, depressed areas smooth, internal lamina 

 having naillike projections. Opercular valves four, smooth, subequal ; color 

 orange. Breadth 4 lines, altitude 2 lines. 



I am giving copies of Costa's description and figures in order to 

 direct attention to this lost species, which will probably be found 

 again in the throat of sea turtle. I suspect that it may be identical 

 with S. prcegustatov, yet the differences in the color and the external 

 sculpture of the parietes, // not due to careless drawing., may indi- 

 cate a distinct species. 



STOMATOLEPAS PR^EGUSTATOR Pilsbry. 



Plate 68, figs. 1, la, 1?). 

 1910. stomatolepas pratjustator Pilshuy, American Naturalist, vol. 44, p. 

 304, fig. 1. 



Type.—C?ii. No. 1851 A.N.S.P., from Tortugas, Florida, par- 

 tially embedded in the mucous membrane of the upper end of the 

 gullet of Caretta caretta. Edwin Linton. 



General form is that of a broad, shallow bowl, the diameter of 

 the base about half that of the oral orifice. The inner layer of the 

 compartments is thin, white and glossy, and projects well above the 

 outer laj^er, the upper ends of the compartments being smooth, 



