THE SESSILE BARNACLES. 



69 



giving it the same rank as the other races subordinated to B. tintin- 

 nabulum. 



Some specimens in the collection of the Academy of Natural 

 Sciences of Philadelphia, received from Frederick Stearns, are labeled 

 "West coast of Lower California." Part of them are cylindric, with 

 lengthened bases. 



Darwin mentions a form of B. tintinnabulum from the coast of 

 Mexico and California which is "rugged and of a dull bluish-purple" 

 color, with "opercular valves exactly like those of var. coccopoma. 

 I have not seen it. 



11 



Locality. 



Collector 



Museum. 



Panama, on oysters . 



Panama 



Salinas Bay. Costa Rica 



Bottom of U. S. S. Portsmouth after 



leaving Guayinas, Mexico. 

 Mazatlan, Mexico 



Dr. W. S. W. Ruschenberger, 



United States Navy. 



Samuel N. Rhoads 



Anastasio Alfaro 



Dr. W. II. Jones, United States 



Navy. 

 Dr. Paul Bartsch 



Academy of Natural Sciences, 

 Philadelphia. 



Do. 



Do. 

 United States National Museum. 



Do. 



BALANUS TINTINNABULUM CONCINNUS Darwin. 

 Plate 16, fig. 3; plate 17, figs. 5-8. 



1854. Balanus tintinnabulum, var. concinnus DARWIN, Monograph, etc., p. 196, 



pi. 1, fig. e; pi. 2, fig. Ig. 

 1903. Balanus tintinnabulum, var. concinnus GRUVEL, Nouv. Archives du Muse'um 



4ser., vol. 5, p. 126. 

 1909. Balanus tintinnabulum Linnseus, PILSBRY, Proc. U. S. Nat. Mus., vol. 37, 



p. 65, pi. 16, fig. 3; pi. 18, figs. 5-8. 



Type. British Museum. 



Distribution. Straits of Magellan to Peru. 



The barnacle is large, cylindric, or somewhat conic, the orifice 

 usually large. The parietes are nearly smooth or a little roughened, 

 sometimes striate, sometimes weakly plicate; with many longitudinal 

 lines and waved, transverse, narrow streaks of livid purple and livid 

 violet on a whitish ground, producing a finely speckled pattern. Radii 

 broad, with horizontal summits; violet-plumbeous. Alae with nearly 

 horizontal summits. Sheath livid purplish with paler al&3. 



The scutum (pi. 15, fig. 3; pi. 17, figs. 6, 8) has the basi-tergal 

 corner a good deal cut off, the deflected tergal segment broad; external 

 growth-ridges rather coarse and prominent; longitudinal strise usually 

 conspicuous. Adductor ridge acute and prominent, broadly overhanging 

 the deep and large pit for tlie lateral depressor muscle. The rostral 

 depressor pit is often bounded by a small rib. 



The tergum is substantially as in B. t. tintinnabulum, except that it 

 is conspicuously striated longitudinally between the narrow growth- 

 ridges, the stria3 coarse on - the scutal side of the closed furrow, fine on 

 the broader side. Spur separated from the basiscutal angle by twice 

 its own width. 



4729 Bull. 93166 



