THE SESSILE BARNACLES. 183 



1839. Balanus fissits ANTON, Ycrzeicliniss meiJier Conchyliensammluag, p. 



108, No. 32!>L>. 

 1841. Bahtniis palinnlalKS Lamarck, DELESSERT, Receuil de Coquilles de- 



crites par Lamarck, pi. 1, fig. 12. 

 1841. Balanus orularis Lamarck, GOULU, Invertebrata of Massachusetts, 



p. 17, 1st pi., fig. 7. 

 1841. Balanus clonyalus Limueus, GOULD, luvertebrata of Massachusetts, 



p. 18, 1st pi., fig. 8. 

 1844. Balanus interrupt us DE KAY, Zool. of New York, Mollusca, p. 252 



(Long Island Sound, on rocks). 

 1847. Chtlia mains ycrmanns and (". pJiilippii FRKY and LEUKART, Beitrh'ge 



zur Kenntniss Wirlu'l loser Thiere, p. 1G7 (Heligoland). 

 1854. Ba fan us lalanoidcs Linnceus, DARWIN, Monograph, p. 2G7, pi. 7, 



fig. 2rt~2(7. 

 1SG3. Balanus balanoidcs Darwin, STIMPSON, Proc. Acad. Nat. Sci. Phila., 



p. 140 (Port Foulke). 

 1882. Balanus balanoidcs Linnreus, LEIDY, Proc. Acad. Nat. Sci. Phila., 



p. 224 (variation at Bass Rocks, Mass.). 



1897. Balanus balanoidcs Linn:cn.s, WELTNER, Verzeichnis, p. 269. 

 1892. Chthainalns europa'iis PHILIPPI, MS., according to WELTWEE, Zoolo- 



gischer Jahrbiicher, vol. 6, p. 454. 



Type. Lost ; from the coast of Sweden. 



Distribution. From latitude 66 34' north, in the Arctic Ocean, to 

 the ocean coast of France, and to Delaware Bay ; x in the Pacific 

 from Unalaska to Sitka. Station, between tides, chiefly on stones, 

 wood, and shells (Mytilidce}. 



The barnacle varies in form from a rather low cone with small 

 orifice, and more or less ribbed or folded walls, to cylindric or club- 

 shaped and much lengthened; dirty white. Conic forms are rather 

 solid, but the lengthened varieties are often fragile. The opercular 

 valves are sunken very little below the peritreme. 



The opercular valves are very similar to those of B. crenatus, but 

 in the scutum there is a callus running downward from the lower end 

 of the articular ridge. The tergum has a very strong triangular 

 articular ridge, and the inflection of the scutal margin is unusually 

 broad. The spur is short, rounded distally, and about half its own 

 width from the basiscutal angle. 



The inner faces of the parietes are smoothish, or have low, irreg- 

 ular, or branching ridges, but no ribs, and there is never any denticu- 

 lation at the base. The parietal pores are small, rounded, or irreg- 

 ular; the septa between them sometimes branching near the outer 

 lamina of the wall ; or sometimes they are entirely filled up, the wall 

 appearing to be solid when viewed from the base. If the outer lamina 

 is eroded or ground down, it will be seen that there are numerous 

 parietal tubes, transversely septate, or sometimes in part filled up 



i Darwin gives the locality Delaware. I have not myself taken it south of Ocean City, New Jersey. 

 Northward the United States National Museum has specimens from Cumberland Gulf or Sound, a little 

 short of the high latitude given by Darwin and quoted above. 



