74 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 37. 



arched, with the two ends aearly alike, umbo near the middle ; some- 

 times it is wanting; terga small or, in adults, sometimes wanting. 

 Lateral filaments numerous; mandibles with five finely pectinated 

 teeth ; maxillae with distinct steps. Caudal appendages none. Cirri 

 with the spines arranged comb-like. 



These pelagic forms live on whales' " bonnets," turtles, the bottoms 

 of ships, buoys, etc. The two species are nearly or quite world-wide 

 in distribution. C. im^gatum is a handsomely striped form, with the 

 plates rather well developed, though small, and without fleshy ear- 

 like processes. It has been reported from Iquique, Chile, and from 

 California. While not yet known from Peru, it doubtless occurs on 

 that coast. C. auritum is readily known by the two large "• ears " 

 rising behind the positions of the terga. The terga and carina are 

 very small, sometimes absent in adults. 



CONCHODERMA AURITUM (Linnaeus). 



1907. C. auritnm Linnfens, Pilsbry, Cirripedia of the U. S. National Mu- 

 seum, Bull. IT. 8. Nat. Mus., No. 60, p. 99, pi. 9, flg. 2. 



Locality. — Tumbez, on Coronula diadema growing on a whale 

 (Weltner). 



