CIRRIPEDIA FROM THE PACIFIC COAST OF NORTH AMERICA. 



203 



Balanus evernianni, n. sp. 



[PI. VII, fig. 7-14: pi. VIII. fig. 1-4; pi. .x, fig. 1: pi. xi. fig. 1.] 



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

 the diameter. The compartment plates are not permeated by pores, and the sutures are 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 showing remnants of a thin yellow 

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

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

 serrate. The parietes of the two carino-lateral plates are verj' narrow; those of the other plates are mod- 

 erately wide; all are weakly sculptured with more or less obliquely transverse wrinkles or ripples, narrow 

 but widely spaced. The radii ha\-e finer gi-owth ripples nearly parallel to the tube, and are lanceolate, 

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



Fig. 4. — Balanus tvt-rjnanni. a, Ma.villa; b. spcon<l cirrus; 



elsewhere smooth. Internally the plates are closely but not strongly striated near the l)ase. The .sutures 

 are smooth and even. 



The opercular valves are white under a thin yellow cuticle. The scuta (pi. vui, fig. 3, 4) have the 

 occludent and tergal margins straight, crenulatcd at the edge. The adductor muscle impression is 

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

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

 deeply and subregularly marked with oblique riljlets in the direction of growth lines. 



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

 crowded. The longitudinal furrow is open. The apex is not beaked. Scutal margin straight; carinal 

 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. Thi! 

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



Scutum, length 41 mm., 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 i. Length of cup loO; 

 greatest antero- posterior diameter 67 mm., lateral diameter G6 mm. (station 4253). 



