26 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



localities are: Albatross station 2268, off Hatteras, north latitude 

 35 10' 40"; west longitude 75 06' "lO", in 68 fathoms, bottom tem- 

 perature 71.3 F., and station 2269, in the same locality, 48 fathoms, 

 bottom temperature 77 F. On the Pourtales Plateau, 10 miles 

 south of Key West, yacht Eolis, J. B. Henderson, jr., 1911, all on 

 spines of Doroddaris. Off Florida, in 195 fathoms, Blake Expedi- 

 tion, in the Museum of Comparative Zoology. 



V. alba has a very considerable geographic range greater than any 

 other American species so far as we know, but it seems t'o be restricted 

 to moderate depths, and it will be noted that the northern stations 

 have about the same high bottom temperature as the southern, and 

 all lie in the course of the Gulf Stream. 



The barnacle is white, flat topped, with steep or subvertical walls. 

 The movable scutum is strongly convex between the apex and basal 

 margin, the apex being depressed and somewhat twisted. It has 

 three articular ridges and two (or sometimes three) longitudinal ridges 

 on the occludent area. The movable tergum has four articular 

 ridges, the second one very small in the type-specimen (but nearly as 

 large as the others in another). The fixed scutum and tergum have 

 conspicuous, stout, recurved beaks. The carina and rostrum inter- 

 lock by one long and some small teeth in each; and above the upper 

 articulating rib both carina and rostrum have several short riblets 

 curving toward and terminating on the scutotergal liinge line. There 

 is a shallow adductor pit in the fixed scutum bounded below by a 

 curved adductor ridge. The fixed tergum is calloused inside. The 

 basal edges of the wall are very obtuse, rather thick. 



Length 4, breadth 2.7, height 1.7 mm. 



The cirri are very slender. The first has rami of 11 and 21 seg- 

 ments, the anterior ramus not much exceeding one-third the length 

 of the posterior. Cirrus ii similar, of 9 and 19 segments, the anterior 

 ramus a third as long as the posterior. The rami of cirrus iii are more 

 nearly equal, the anterior three-fourths the posterior. Cirrus vi 

 about 3.3 mm. long. The terminal appendage is 2.8 mm. long, with 



27 segments, being nearly four times as long as the protopod of 

 cirrus vi. 



The above details from the original specimens, together with the 

 figures given in my former account, show that V. alba is widely 

 distinct from V. nexa Darwin, of which I formerly thought it might 

 be a variety. 



The specimens are apparently adult, judging from the long beaks 

 of the fixed scutum and tergum, and the thickness of the wall plates. 

 The specimens from off Hatteras, one from each of the stations men- 

 tioned above, are typical in form and sculpture and of about the 

 typical size, one measuring: carinorostral length 3.9, breadth 2.8, 

 alt. 1.9 mm. Specimens from other places differ in some respects. 



