104 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



Tergum triangular, with a long spur more than its own width from 

 the basiscutal angle. The spur is continued as a rounded ridge on 

 the inner face of the valve; borders of the external furrow folded 

 closely together. This appears to be a lateral branch of the B. c. 

 proteus stock. 



Balanus finchii Lea, from St. Marys, Maryland), 1 may be a very 

 young specimen of this race, but it is smooth, and the opercular valves 

 are unknown. The young of chesapeakensis should be strongly cos- 

 tate. 



There are probably one or more races of the concavus group in the 

 Atlantic slope Miocene, in addition to those already mentioned. 

 Darwin's figures, 4h, 4i, 4Jc, represent a Maryland form unlike any I 

 have seen. The subject deserves further investigation with much 

 more material than I can command. 



BALANUS CONCAVUS PACIFICUS, new subspecies. 

 Plate 23, figs. l-2c. 



Type.C&t. 32953, U.S.N.M., from San Diego, California. 



Distribution. Northern California to Callao, Peru; Pliocene and 

 Pleistocene of California. 2 



The barnacle is conical (or cylindric), with a diamond-shaped 

 orifice with the peritreme but slightly toothed; smooth, the wide 

 radii but slightly sunken; striped with vinaceous or deep vinaceous 

 on a much paler or white ground, the radii and sheath vinaceous or 

 white. Epidermis thin and transparent, usually persistent on the 

 parietes. The opercular valves have more or less vinaceous coloring, 

 chiefly inside and near the apices. 



Greatest diameter 34 mm.; height 20|- mm. (type, pi. 23, fig. 1). 



Greatest diameter 25 mm.; height 55 mm. (cylindric; San Pedro). 



Greatest diameter 22 mm.; height 26^ mm. (cylindric; Crescent 

 City). 



Greatest diameter 18 mm.; height 9 mm. (conic; Crescent City). 



The scutum has rather low growth-ridges and close, unequal, radial 

 strix throughout. The articular ridge is small, reflexed and not much 

 over half as long as the tergal margin. Adductor ridge high and long, 

 approaching the basal margin. A thin but high ridge bounds the 

 lateral depressor muscle insertion, its crest usually curving toward it, 

 to form an imperfect tube. 



The tergum is broad, triangular, with a nearly closed furrow to 

 the spur. Spur rather long, separated by its own width or less from 

 the basiscutal angle. The scutal border is but slightly inflected. 

 Crests for the depressor muscles are moderately developed, weakening 

 near the basal margin. Articular ridge is low. 



Contr. to Geol., p. 211, pi. 6, fig. 222. 2 See Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 344. 



