22 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



smooth; their basal borders are broadly inflexed (fig. 2). Both mov- 

 able valves have three very low, flat ribs. 



The movable scutum has the usual crescentic rib, a broad, flat, 

 strongly projecting median articular rib, another very narrow one 

 above it, the rest of the plate having well-spaced, narrow, transverse 

 grooves. Inside there is a deep, oblique articular furrow near the 

 apex, receiving the upper articular ridge of the tergum. This is 

 bounded inside by a short, high ridge back of which is the rather deep 

 pit of the scutal adductor muscle. Nearer the basal edge there are 

 several low callous lumps, variable in form and position (fig. 5.) 



The movable tergurn has a deep recess in the middle of the scutal 

 border, at the termination of a median articular rib ; above this there 

 is a flat, wide upper articular rib, and below it a narrow diagonal 

 rib. The rest of the plate is transversely grooved. The internal 

 face (fig. 5) is nearly flat. 



The fixed scutum has only faint sculpture of growth lines outside, 

 or sometimes the triangular area next the occludent edge is vertically 

 grooved. The beak is not produced, but lies in close proximity to 

 that of the movable scutum. From the inside wall a prominent 

 semicircular adductor ridge or myophore depends, concave on its 

 upper face (fig. 3.) Externally, there is a very small radius in the 

 tergal suture; below a small ala on the fixed tergum. 



The fixed tergum is about as large as the fixed scutum and similarly 

 sculptured. 



The carina and rostrum articulate by a suture weakly zigzag 

 below, but the carina has one large tooth above, between two smaller 



1 Some material preserved dry was labeled as from Albatross stations 26C2-3, 2669, 2671-2. Among other 

 organisms it contained fragments of coral and more or less perfect examples of the following Cirripedia: 

 Scalpdlum longicarinatum Pilsbry. 

 Calantica superba (Pilsbry). 

 Verruca coraliophila Pilsbry. 

 Hcxdasma americanum Pilsbry. 

 These stations are situated as follows: 



Coral was reported from stations 2669 and 2671. Material preserved wet from station 2669 contained the 

 typesof Calantica superba; the type of Hcxelasma americanum is from station 2663; and thatof Scalpdlum 

 Innijicarinatum is from station 2668. It is therefore impossible to draw any inference as to the particular sta- 

 tion or stations which supplied the barnacles of this mixed lot, but this is hot of great importance since all of 

 the stations in question are in the same district, and except the last two they do not differ much in depth 

 or temperature. 



