. Bulletin - United States National Museum. Science. THE SESSILE BARNACLES. 67 Scutum dull purple, with smooth growth-ridges. Adductor ridge strongly developed, rather acute. Terga white, shaped as in B. t. tintinnahulum, with a rather short, acute beak; the external furrow closed; spur narrow; scutal margin smooth. The labrmu has a small median notch and no teeth on the shortly hairy edge. Mandible with five well-developed teeth, the last united with the lower point (fig. 11a). Maxilla has 13 large spines, about as in B. t. tintinnahulum. Curi about as m B. t. tintinnahulum, except that the s
. Bulletin - United States National Museum. Science. THE SESSILE BARNACLES. 67 Scutum dull purple, with smooth growth-ridges. Adductor ridge strongly developed, rather acute. Terga white, shaped as in B. t. tintinnahulum, with a rather short, acute beak; the external furrow closed; spur narrow; scutal margin smooth. The labrmu has a small median notch and no teeth on the shortly hairy edge. Mandible with five well-developed teeth, the last united with the lower point (fig. 11a). Maxilla has 13 large spines, about as in B. t. tintinnahulum. Curi about as m B. t. tintinnahulum, except that the segments of the three posterior cirri are not so short, and the lower pair of spuies on each segment is smaller (fig. lib). The above description applies to solitary specimens (figs. 2 to 2d) not encrusted by nullipore, algie, or other marine growths. In the. Fia. 11.—a, Mandible, and &, median segment of cirrus vi, of Balanus t. peninsularis. C, MEDIAN segment, CIRRUS VI, OF B. T. AZORICUS. large series comprised in Cat. No. 43487, , the barnacles grow hi clusters (figs. 1, la), and are overgrown with algse, etc. The spines in this lot are less fully developed, usually appearing only on some of the compartments, the others being irregularly ribbed, plicate, or nearly smooth. Some individuals lack spines altogether. The radii are often smooth, rarely striate throughout. The color may be soiled white tliroughout, or like the type, or lineate and clouded with Uvid purple, the radii bcmg livid purple, shading into white along one side. The opercular valves are similar to the typical form. I worked over this race a long time in an attempt to identify it with one or other of Darwin's named forms of B. tintinnahulum, finally deciding to give it subspecific rank. Darwin's accomifc of B. t. dorhignyi Chenu, and Chenu's figure, resemble peninsularis rather closely, yet differ by the oblique summits of the radii. Chcnu gives no figure of the opercular valves, and Darwin says
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