BIOLOGICAI, SURVEY OF WOODS HOLE AND VICINITY. 1 29 



(p. 89) that a greater number of cirripedes have been catalogued from Woods Hole 

 than from any of the other stations considered in our table. Only 10 species each 

 have been listed by Whiteaves, Herdman, and the Plymouth laboratory, while 15 have 

 been recorded by Graeffe. Six of the Canadian species and 4 of those listed for Plymouth 

 are common to our Woods Hole catalogue. 



The barnacles, particularly the sessile forms, are a very baffling group to the tax- 

 onomist, and it must be admitted that our local collections have not received the treat- 

 ment which they deserve. During the greater part of the Survey dredging separate 

 specimens were preser\'ed from each station at which barnacles were taken. A large 

 proportion of these specimens were immature, many others were waterwom and imper- 

 fect. The small collection made during the summer of 1903 was examined by Dr. H. A. 

 Pilsbry, who furnished a list of identifications covering this earlier period. The survey 

 was unable to obtain the ser\'ices of this specialist in determining the barnacles dredged 

 during the subsequent seasons of the work." This task was finally undertaken by the 

 senior author of this report, who offers his results with considerable reservation. Atten- 

 tion must be called to the frequently reiterated statements of Darwin, the chief monog- 

 rapher of this group, respecting the high variability and the indefinite limits of the 

 species of Balanus. As evidence of the impossibility of distinguishing these species by 

 external characters, he writes (Monograph of the Cirripedia, vol. 11, p. 187) : "After hav- 

 ing described nearly 40 species, and when my eye was naturally able to appreciate small 

 differences, I began carefully to examine varieties of B. tintinnahulum, amphiirite, impro- 

 visus, porcalus, vestitus, etc., without even a suspicion that they belonged to these species, 

 at that time thoroughly well known to me." It must be added, however, that the case 

 is far less difficult to one who deals with a very few species occupying a very limited area. 

 Unless certain species which have never been reported from the Woods Hole Region are 

 nevertheless common here, our determinations are probably correct in the great majority 

 of cases. 



By far the larger proportion of specimens coming from the Survey dredgings which 

 have been examined have been referred to Balanus eburneus. Large specimens of this 

 species, found upon the bottom of a boat and elsewhere, have been studied carefully, 

 with reference both to the internal and external structure of the shell. The same careful 

 examination was extended to certain of the specimens coming from the dredgings. 

 None of the latter, however, nearly equaled in size the examples taken from woodwork 

 in shallow water, and are probably for the most part immature. The longitudinal 

 striation of the terga is faintly indicated, or altogether wanting, and the general shape 

 of the opercular plates differs from those taken from adult specimens. It must be 

 confessed, therefore, that general appearance and the process of elimination have 

 led us to our decision in regard to most of these specimens. They are obviously 

 not to be referred to Balanus balanoides, for they have a shelly base, and differ in other 

 conspicuous ways. Moreover, the latter species is strictly intertidal in its habitat. 

 Nor are they to be assigned to Balanus crenaUis, B. porcatus, or, indeed, to any of the 

 other species which have thus far been recorded from this region. At least one source 

 of serious confusion seems to be possible, however. Darwin tells us that "diagnosis 



o We are indebted to him, however, for the identiiicatioa of a considerable number of stalked barnacles of the genera Lepas 

 and C<m<hodprma. 



16269° — Bull. 31, pt I — 13 9 



