362 PROCEEDINGS OF THE ACADEMY OF [Julv, 



The ■torc:;um is wide and triangular, the scutal and carinal margins 

 straight. It is sculptured externally like the scutum; without a dis- 

 tinct spur, which is represented only by a slight wave in the basal mar- 

 gin. Internally there is a very short articular ridge and furrow; 

 elsewhere the surface is irregularly roughened with short rugae and some 

 longitudinal wTinldes converging to the apex. 



Height of the wall (to base of carina) 18 mm.; length of base 11, 

 breadth 9.2 mm. 



San Ysidro, Lower California. Type No. 1,783, A. N. S. P., collected 

 and presented by C. R. Orcutt, 1889. There are also specimens from 

 the same place and collector in coll. U. S. National Museum. 



The barnacles live wholly imbedded in sponges and can be found 

 only by breaking them up. Balanus orcutti differs from B. dcclivis 

 Darwin^ of the West Indies, by the peculiar sculpture of the external 

 surface, which is obliquely corrugated or tuberculate in places, and by 

 the shapes of the opercular valves. In B. dcclivis the scutimi is wider, 

 its greatest breadth contained twice in the length, while in B. orcutti 

 the breadth is contained fully two and one-half times in the length. 

 The tergurn, on the other hand, is wider in B. orcutti, with a much less 

 developed "spur," and a less wide inflected scutal area is seen in the 

 interior view than Darwin figures for B. declivis. These characters 

 show no noticeable variation in the series examined. 



The specimens are dry, and the cirri and other internal parts have 

 been destroyed. 



Explanation of Plate XXIX, 



Fig. I. — Balanvs orcutti, carinal view of the wall. 



Fig. 2. — Lateral view of the wall. 



Fig. 3. — Rostral view of the wall. 



Figs. 4. .'5. — Interior and external views of the scutum. 



Figs. 6, 7. — Interior and external views of the tergum. 



^ Monograph on the Cirripedia, Balanidoe, p. 275. B. d.edivis has also been 

 reported from Batian, Moluccas, bv Weltner, Verz. rccenten Cirrivedenarten, p. 

 270. 



