CIKRIPKDIA FROM THK PACIFIC COAST OF NORTH AMERICA. 



203 



Balanus evermanni, n. sp. 



[PI. vir, fig. 7-14; pi. viii, fig. 1-4; pi. x, fig. 1; pi. xi. tig. 1.] 



The outer wall ia cup shaped, wider above than at the base; the length generally much exceeding 

 the diameter. The compartment plates arc imi permeated by pores, and the sutures arc not calcified or 

 firmly cemented. The heavy calcareous base is likewise imperforate, and the suture where it joins the 

 plates is but very weakly cemented. Surface dull, white, often shewing remnants of a thin yellow 

 cuticle. The orifice is very large, not contracted, and squarish nr ovate, being narrower and more 

 strongly angular at the carina. All the plates project strongly upward, making the borders of the orifice 



sca-raic The parietes of the two carino Lateral plates are very narrow: those of the other plates are i I 



i rately wide; all are weakly sculptured with more or less obliquely transverse n rinkles or ripples, narrow 

 but widely spaced. The radii have liner growth ripples nearly parallel to the tube, and arc lanceolate, 

 tapering very slowly upward. The wings or alee are very wide, with an external upper striated triangle, 





Fig. 4. — Balanus < <■> rmanni. 



Maxilla; B, sc.-eii. i cirrus;  . ticm-liM 



el ewhere smooth, Internally the plates are closely but nol strongly striated near the base. The sutures 

 are Bmooth and even. 



The opercular valves are white under a thin yellow cuticle. The scuta (pi. vm, fig 3 I have the 



ocelli, lent and tergal margins straight, crenulaicd at the edge. The adductor muscle impression is 



shallow and ill-defined, the lateral depressor muscle impression is deep. The adductor ridge i- a low, 



rounded and wide callous rib. The articular ridge is short and not very prominent. The exte is 



deeply and subregularlj marked with oblique riblets in the direction of growth lint 



The terga are sculptured externally like the scuta, except that the riblets are narrowei and more 

 crowded. The longitudinal furrow is open. The apex is not beaked. Scuta! margin straight; cardial 

 margin slightly convex. The spur is rather long and narrow. Internally the articular ridge is rather 

 low, blunt, but strong. There are four or five short and delicate ridges at the carino-basal angle. The 

 spur is connected with the articular ridge by a strong, rounded and straight rib (pi. vm, fig. 1. 2). 



Scutum, length 41 turn., greatest breadth 18.7 mm. Tergum, length 33 mm., breadth 13 mm. From 

 a specimen in which the longest valve of the cup is 88 mm. long(station 4239). Length of cup 150; 

 greatest antero-posterior diameter 67 mm., lateral diameter 66 mm. (station 4253). 



