MIOCENE AND PLEISTOCENE CIRRIPEDIA FROM 



HAITI. 



By Henry A. Pilsbry, 



Of the Academy of 'Natural Sciences, Philadelphia, 



It is well known to workers on sessile barnacles that while the 

 subgenera of the genus Balanus rest upon differences in the struc- 

 ture of the walls and basis, the specific distinctions are mainly based 

 upon the opercular plates. No species can be considered well estab- 

 lished until these plates are known. Nevertheless, in dealing with 

 forms of a restricted area it is not difficult to assort the specimens 

 into species by characters of the walls alone, and to determine them 

 if all described species of the region in question are accessible for 

 comparison, either as specimens or represented by sufficient accounts 

 of the wall characters. 



Thus, most or all of our American Tertiary Balani can be dis- 

 tinguished from one another by characters of the walls. But part of 

 them can not be compared with species of the European Tertiary 

 which were defined by the opercular j^lates without regard to the 

 internal structure of the wall plates. 



BALANUS, near EBURNEUS Gould. 



A small barnacle, about 11 mm. in greatest diameter. The plates 

 of the wall are smoothish with broad radii, as in B. eburneus. The 

 rostrum has 11 tubes. Except close to the base these are closely 

 septate. The septa are closer than in any B. ebwnveus examined, but 

 in the absence of opercular plates the significance of this difference in 

 a single specimen is doubtful. B. dibmmeus has been found in 

 Pleistocene deposits of the Panama Canal Zone. 



Station 9464 (W 151 F). Departement de I'Ouest, north edge of 

 Port au Prince, along road leading up to dwelling houses of the 

 Haytian- American Sugar Co. From beds of Miocene age, 75 meters 

 above sea level. One specimen, collected by W. P. Woodring. 



Cat. No. 352256, U.S.N.M. 



BALANUS CONCAVUS ESEPTATUS, new subspecies. 



Plate 1, figs, a, &. 



Conic or subcylindric barnacles of moderate size, similar to B. 

 concavus paci-ficns so far as the walls are concerned. The parietes 

 are smooth, radii wide with oblique summits. The parietal tubes 



No. 2515— Proceedings U. S. National Museum. Vol. 65, Art. 2. 



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