TFIi; SKSSII.K r.AKNACLKS. 



321 



rather wide and deep notch. Occludent margin indexed, a rather 

 deep crease under it for the adductor muscle. No pits or scars for 

 depressor muscles are visible. Length -1.5 mm. (pi. 75, fig. !<"/ also 

 fig. 94). 



The tergnm is extremely thick, narrow, with a rather shallow 

 articular furrow. There is a sort of short spur united with the basi- 

 scutal angle and projecting below it. The carinal lobe of the valve 

 appears pushed upward. Crests for the depressor muscle are rather 

 strong and irregular. 



The numerous specimens of this species have been in the collection 

 many years, and the body was entirely destroyed in those opened. 

 The uniform violet black color of the interior is unusual and char- 

 acteristic. Ckthamalus interteytus Darwin, a Philippine species, 

 is purple within, but other known species are lighter colored or 

 clouded with some dark shade on a lighter ground. 



CHTIIAMALUS CIRRATUS Darwin. 



1854. Chtha mains cirratus DARWIN, Monograph, p. 461, pi. 18, figs. 4, 4&. 

 1909. Clithanialutj cirratus Darwin, PILSBKY, Proc. U. S. Nat. Mus., vol. 37, 

 p. 71, fig. 2. 



Distribution. Pescadores Islands, Peru, to the northern Chonos 

 Islands. 



The barnacle is either depressed-conic, 10 to 13 mm. in diameter, 

 corroded above, ribbed and crenate at the base, when not crowded, 



FIG. 05. CHTHAMALUS CIRUATUS. SAN LORENZO ISLAND, PERU. INSIDE VIEWS OF TERGUM 

 AND SCUTUM ENLARGED, AND GROUP OF TIIREE ENTIRE ANIMALS, NATURAL SIZE. 



or when crowded the walls become vertical, and the orifice and the 

 opercular valves are large. There is also a smooth form. Accord- 

 ing to Darwin, large specimens from Coquimbo and Valparaiso have 

 a height of 1 inch with a basal diameter of half as much. All of 

 those I have seen from Peru are depressed. The interior is usually 

 dull purplish (fig. 95). 



The opercular valves are corroded. The scutum has a long, strongly 

 projecting articular rib, which has a long, nearly straight or some- 

 times convex slope to the deep articular furrow, unlike any form 

 of C, stcllatns. The adductor muscle pit is deep. The lateral de- 



