250 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 



My studies in the group show that the distribution of the races as 

 here defined conforms to that of molhisks and other littoral animals, 

 each of the marine faunal provinces having its race of Tetradlta. 

 They are not scattered haphazard, as one might suppose from the 

 existing literature. 



We have no direct means of knowing the type-locality of 

 Bruguiere's type of squamosys. His references, so far as they can 

 be localized, pertain to oriental forms. The terms of his description 

 apply to either the Panamic or the Chinese and Philippine forms, 

 not to the West Indian. He states that the orifice is small, that there 

 is no trace of radii, and " I'epaisseur de ces valves est tres-considerable, 

 elle egale a la base la moitie du diametre inferieur de la coquille." 

 The opercular valves were wanting in his specimen. It seems far 

 more likely that Bruguiere would have an East Indian than a 

 Panamic barnacle, as oriental shells and barnacles were common in 

 Europe long before his time. 



The type-specimen was probably lost, for the illustrations pub- 

 lished in the Encyclopedic several years later (pi. 165, figs. 9, 10) 

 were copied from Chemnitz. Under these conditions it has seemed 

 best to consider the common form of China and the Philippine 

 Islands as typical T. squamosa. 



Gmelin's L. i:>orosa was also of oriental origin, so far as can be 

 determined. His very brief account was compiled. Lepas fungltes 

 and T. squamialosa were also from eastern sources. Darwin did not 

 assign typical localities for the varieties he described, but inciden- 

 tally he mentioned having var. communis from Pernambuco and 

 the Galapagos Archipelago; var. ruhesccns from the Philippine 

 Archipelago, and var. elegans from California. The Galapagos form 

 may ho, what is herein described as milJeporosa. The Philippine 

 record for ruhescens must have been based upon specimens with an 

 erroneous locality, or upon some oi'iental form which I have not seen. 

 It may be noted here that some obvious errors among localities given 

 for barnacles by Darwin may be traceable to specimens from Cum- 

 ing's collection, which is known to have been the source of numer- 

 ous erroneous localities in the literature of mollusks. It is well 

 known that Cuming trusted to his memory for localities, instead of 

 recording them on the labels at the time the specimens were collected 

 or received. 



KEY TO SITBSPECIES OF T. SQUAMOSA. 



a\ Inflectotl occhidcnt margin of the scutum having few (one to three) oblique 

 teeth or fohls. Tergum narrow, its width not much over one-third its 

 length, the basal margin sloping to, and almost in line with, the carinal 

 border of the spur. California. 

 6\ External wall eroded, reddish; sheath and interior of tergum reddish- 

 purple or tinted T. s. ruhescens 



b\ External wall not eroded, whitish T. s. ruhescens, form elegans. 



