304 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



It appears, then, that this typical form of the species is known 

 from the Mediterranean, Madeira, and the Azores; whether it 

 occurs in northern Europe is still uncertain. 



Darwin figures (pi. 18, fig. Ik) a peculiar form which I have not 

 seen, from St. lago, Cape Verde Islands. 



Northern Europe. Form punctatus Montagu (pi. 71, figs. 2-25, 

 3, 3#) . In English specimens there is a good deal of variation from 

 the characters given above. The external form is often typical, 

 as in plate 71, figures 3, 3a, from Exmouth ; but when crowded they 

 become cylindric, as in plate 71, figures 2, 2, 25, exceedingly like 

 the cylindric form of Balanus balano-ides. This tubular form is 

 what Professor Gruvel has called var. fistulosus. There are many 

 transitional specimens between the tubular and the depressed forms, 

 in the same groups. 



The scutum, in all of the English examples I have closely exam- 

 ined, is longer than in the Mediterranean form, with the apical angle 

 acute, the tergal margin shorter, and the adductor muscle pit smaller. 

 The tergum also differs by having a sinuation in the basal margin 

 near the depressor muscle crests. I have not taken time to compare 

 large series the cleaning is somewhat tedious but according to 

 Darwin these characters of the valves vary so much that he included 

 all of them in var. communis. If the form in question proves to be 

 racially distinguishable from typical stellatus it will be called punc- 

 tatus Montagu. Eroded specimens usually have a punctate or pep- 

 pered appearance. M}^ plate 71, figures 2-25, 3, 3<?;, and Darwin's 

 plate 18, figure !<:>, are from British specimens of this race. 



CHTHAMALUS STELLATUS DEPRESSUS (Poli). 



1791. Lcpas flcpressa POLI, Testacea utriusque Sicilite, vol. 1, p. 27, pi. 5, figs. 



12-17. 1 

 1818. Chthamalus glaltcr RANZANI, Opuscoli Scientific!, vol. 2, p. 83, based upon 



Lcpas depressa Poli. 

 1854. Clitliamalus steUatus var. depresses Poli, DAEWIN, Monograph, pi. 18. 



fig. Ib (locality not given), ly (Mediterranean). 



name Lcpas depressa has page priority over L. stcllata, but subsequent authors 

 have preferred the latter, depressa being a far less common and local form. 



