100 



BULLETIN 60, UNITED STATES NATIONAL MUSEUM,. 



Genus HETERALEPAS Pilsbry, new genus, 



1851. Alepas Darwin, ^Monograph on the Cirripeilia, Lepadidjt, p. 156, exclusive 

 of A. parasita. 



Nude barnacles, with the muscular la3'er of the peduncle continued 

 within the integument of the capitulum; scuta absent, or minute and 

 chiefly chitinous; no other plates developed. Cirri long, man}" jointed, 

 of the usual curved form, with spines in tufts on the distal ends of 

 the segments. Jointed caudal appendages present. Attached to 

 objects on the bottom. 



'Type.—H. re.,' (Pilsbry). 



This genus comprises all the species referred to Alepas by Darwin, 

 Hoek, Aurivillius, Gruvel, Annandale, and other authors, with the 

 exception of A. parasita Rang, the t3'pe of Alejpas. The type of 

 HeteraJejMS is a large Hawaiian species originally described as Aleixis 

 rex. 



Fig. 34.— Segments from the Oth cirrus of {A) Parai.ep.^s pekcarinata, (Si Heteralepas 

 REX, and (C) Alepas pacifica 



Hetexalepas consists of two series of species, whicli will probably be 

 separated eventually as distinct genera. 



In typical IlettralejMs the inner rami of cirri v and vi are greatly 

 reduced in size and number of segments, with the spines of the anterior 

 border atrophied, small and weak. The outer rami of cirri v and vi, 

 and both in cirri ii to iv, are very long, composed of extremel}" numer- 

 ous short segments, each armed with two or three yqvy long spines 

 and three or two minute ones at the anterior distal angle, and a group 

 of several small spines at the posterior distal angle (tig. 34^, two inter- 

 mediate segments of cirrus vi of //. re,i). 



In the new subgenus Paralepas the cirri ii to vi have subequal 

 rami of comparatively few segments, each armed with a semicircular 

 ))rush of man}" short spines on the anterior face and a group of several 

 (about three) long stout spines at the posterior distal angle of each 



