120 



BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



spines near the distal border, but no teeth. The posterior ramus has 

 teeth on six segments. Cirrus iv has a few minute teeth near the 

 distal borders of some segments of the anterior (outer) ramus. 

 Cirri v and vi have two pairs of spines on most of the segments, but 

 on a few there are three pairs, the lower ones small (fig. 32a.) 



The penis is extremely long. No point seen on its dorsal base. 



This common Antillean form was briefly described but hot named 

 by Darwin, who hesitated between describing it as a species and 

 placing it under B. spongicola as a variety. His specimens were from 

 St. Vincent, on coral, and others on an Avicula without definite 

 locality. Having studied a long series of B. spongicola and several 

 hundred B. calidus, I do not hesitate to give the latter specific rank. 

 The ribbed wall, the finer and shallower longitudinal striation of the 

 scutum, and the broader tergum, with wider spur, its carinal margin 

 making an angle with the basal margin, are all characteristic. The 

 opercular valves are not only actually but also relatively smaller than 

 in B. spongicola. By the distinct ' ' teeth ' ' of the segments of the third 

 cirrus it approaches B. trigonus. So far as I know, B. spongicola 

 does not have the armature so strongly developed. The spines of 

 the posterior cirri are slightly more reduced than in B. spongicola, or in 

 fact than in any Balanus I have dissected. The other characters 

 of the barnacle are about as in B, spongicola. 



B. calidus lives in populous colonies on shells of all kinds, dead 

 echinoderms, and even on the spines of echini (Cidaris trihuloides) , 

 an unusual station for Balanus, though a favorite one for VeiTuca. 

 The largest specimen seen has a diameter of 10 mm., height 8 mm. It 

 is from Albatross station 2365. 



Note.— Station 2372 is in the vicinity of Cape San Bias, or Appalachicola, western Florida. Stations 

 2405, 2407, 2403 are further offshore in the same region. Stations 2360-2365 are on the Yucatan Bank, north 

 of the northeastern extremity of Yucatan. 



Series of B. perforatus. 

 BALANUS L^VIS Bruguiere. 



Plate 27, figs. 1, la, 3-36. 



1789. Balanus Ixvis Bruguiere, EncyclopMie Methodique, p. 164, pL 164, fig. 1. 

 1818. Balanus discors Ranzani, Opuscoli Scientifici, voL 1, p. 77, pL 3, figs. 9-13. 

 1854. Balanus Isevis Bruguiere, Darwin, Monograph, p. 227, pi. 4, figs. 2-25r, 

 with var. nitidus, fig. 2, and var. coquimbensis, fig. 2a. 



