70 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.37. 



the basal margin. The outer face of the phite is flat, except that the 

 scutal border is turned up a little; there is no longitudinal furrow, 

 but two impressed lines run from apex to the sides of the spur. The 

 surface is marked with concentric striae and low, flattened riblets, 

 much less conspicuous than on the scutum. There are also numer- 

 ous unequal radial striae, chiefly on the carinal half of the plate, and 

 mostly rather weak. Inside there is a broad and rather deep articu- 

 lar furrow^ and a massive though not high articular ridge. The 

 crests for the depressor muscle are high, acute, and project beyond 

 the basal margin of the plate. The carinal half of the interior is 

 finely I'ugose throughout. 



Carino-rostral length of the base 31 mm.; width, 28.5 nnn. ; height, 

 23 mm. Length of the scutum, 10.5 mm. ; width, 5 mm. Length of 

 the tergum, 8 mm.; width, 5 mm. 



This species is related to B. glandida Darwin of California. It 

 differs from that species chiefly by the shape of the scutum, w^hich is 

 narrower than in B. glandida^ and differs in the shape and propor- 

 tions of the ridges of the interior. (Compare Darwin, Balamdw^ pi. 7, 

 fig. \a). B. glandula^ moreover, has the "walls rugged, longitudi- 

 nally folded." B. trigonus Darwin differs by having rows of pits 

 on the scutum and longitudinal ribs on the parietes. It is almost 

 identical with 'peruinanu8 in the shapes of the opercular plates. 



The pores of the parietes are filled up except close to the base, and 

 might readily be overlooked. The base is solid. In these features 

 B. peruvlanus resembles B. glandida and B. trigomis. Unlike B. 

 patellaris (Spengler), the base (Miryes to fit the shape of the support. 



BALANUS TRIGONUS Darwin. 



1854. Bulanuft trigonus Dakwin, JNIonograpli on the Cirripedia, Balanidje, 

 p. 223, pi. 3, figs, lu-lf. 



Locality. — Peru, without special locality (Darwin). Also reported 

 from (California, Australia, and New Zealand (Darwin). The origi- 

 nal description by Darwin is as follows: 



Shell conical, generally depressed; parietes ribbed, mottled pnrplish red; 

 orifice broad, trigonal, hardly toothed. Scutum thick, with from one to six 

 longitudinal rows of little pits. Tergum without a longitudinal furrow; spur 

 truncated, fully one-third of the width of valve. 



The scutum and tergum resemble those of B. peruvkim/^ in outline, 

 but differ in sculpture. No definite locality in Peru has been 

 recorded. 



Genus CHTHAMALUS Ranzani. 



Barnacles like Balamis in general appearance, but the rostrum has 

 alae, or underlying side areas, while in Balunus these areas lie over 

 the adjacent edges of the lateral compartments. They are small 



y. 



