THE SESSILE BARNACLES. 139 



1911. Balanus rosfrntns Hoolc Pri.sp.EY, Bull. Biu\ of Fisheries, vol. 29, p. 

 73, pi. 12, fig. 6 (issued Feb. 17). 



1911. Balanus rostratus Hoek, Kuuger, Beitriige zur Cirripedienfauua 

 Ostasiens, Abh. math.-phys. Klasse der K. Bayer. Akad. der Wissen- 

 schaffen, Suppl.-Bd. 2, p. 52. 



1911. fBalanus crenatits Bruguiere, Kkugee, Beitriige zur Cirripedienfauua 

 Ostasiens, Abh. niath.-pbys. Klasse der K. Bayer. Akademie der 

 Wissenschaften, Suppl.-Bd. 2, p. 52, figs. 105-107; pi. 4, figs. 36 (Sag- 

 ami Bay and Yokohama). 



Type. — British Museum, from Kobe, Japan, in 8-50 fathoms. 



Distrlhutlon. — North Pacific: Ocean coast and InUind Sea of 

 Japan ; varieties in Bering Sea and Puget Sound. 



The barnacle is strong and rather thick, conic, with a rather small, 

 ovate orifice, moderately wide, deeply sunl'en radii, very narrow 

 carinolateral compartments, and broad lateral and rostral com- 

 partments. Surface smooth or somewhat folded, not regularly or 

 distinctl}^ ribbed; partially covered with a very thin pale-buif 

 epidermis. 



The scutum is like that of B. balanus externally. There are nar- 

 row, prominent ridges of growth, somewhat imbricating downward, 

 and crenulated by the fine, deep longitudinal striation which runs 

 over ridges and intervals. The articular ridge is very low ; articular 

 furrow very narrow and shallow. The adductor ridge is low, often 

 weak; it stands free of the articular ridge, and bounds the rather 

 deep pit of the depressor muscle. 



The tergum is ichite. flat, with sculpture of growth-ridges and weak 

 longitudinal stria?. A narrow fasciole runs to the spur. The spur is 

 Avide at the base, but tapers to a narrow, obliquely truncate end. The 

 scutal margin is only narrowly inflected. Articular ridge moderate. 

 No ridge runs to the spur. Crests for depressor muscles are weak or 

 wanting (fig. oOa). 



Compartments. — The parieties are angular along the deeply sunken 

 radii, which have the appearance of slits made with a knife. The 

 summits of the radii are level or somewhat oblique and jagged when 

 perfect, but they are usually broken; edges irregularly laminate. 

 Ala? narrow, with very oblique summits. The sheath lies very close 

 to the wall, leaving scarcely any hollows below it. Parietes below the 

 sheath are strongly ribbed. Between the ribs which terminate in septa 

 there are usually from one to four ribs ending in points on the inner 

 lamina of the wall, exactly as in B. hcdanus. Tubes of the parietes 

 large and square, about 14 in number in the rostrum. They have 

 many transverse septa down to the base, as shown in plate 36, figure 

 2«. Outer lamina with many extremely small, short lamella? within 

 the margin. 



Basis thin, radially grooved, without any pores. 



Carinorostral diameter, 42 mm. ; height, 36 mm. 



