BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 179 



since the only shoal so situated (the Middle Ground), lying within the territory dredged 

 by us, is made up to a considerable degree of shifting sand, ill adapted to the support of 

 most animal life. 



It may be well at this point to recall the type of distribution displayed by many 

 species whose occurrence is general in Vineyard Sound, but which in Buzzards Bay are 

 limited to the immediate vicinity of shore. If we had the data for the Bay alone at 

 our disposal, it would be natural to suppose that the species had a definite bathymetric 

 limit. We have, however, the best reasons for believing that it is the muddy character 

 of the bottom, throughout the deeper parts of the Bay, which restricts the distribution 

 of such forms. , 



Whatever be the causes which are responsible for limiting certain species to the 

 shallower waters skirting the shore, it is certainly desirable that we should have a suitable 

 word by which to designate both the fauna inhabiting these waters and the habitat which 

 they occupy. For this purpose we have already employed at various times the term 

 "adlittoral," which, so far as we know, has not been used by previous writers. Were 

 there any unanimity, even among zoologists, in the use of the word "littoral" itself we 

 should have no hesitation in recommending this term adlittoral. But the former word 

 has been applied with very different degrees of inclusiveness, having been restricted by 

 some to the intertidal zone ; while by others it has been so extended as to take in the 

 whole continental shelf. a It is in the more restricted sense that the term has been 

 employed in the present report. For this, the word "tidal" 6 would be unequivocal 

 and, indeed, self-explanatory. But, unfortunately, we could not well speak of a "tidal 

 species," however appropriate the expression "tidal zone" would seem. Again, this 

 word does not lend itself readily to a combination with Latin prefixes such as "sub" 

 and "ad." 



Now the word " sublittoral " has likewise been used with very varying inclusiveness, 

 from "just below the shore line" (Standard Dictionary) to a zone reaching to the greatest 

 depths at which algae flourish (Kjellman) . d This latitude of definition rests upon the 

 inherent ambiguity of the word itself. For there is nothing in its composition to imply 

 a limit of depth, any more than there is in the words "submarine" or "subterranean." 



It is therefore with hesitation that we have chosen the term "adlittoral" as 

 designating the zone of shallow water immediately adjacent to the shore. We have 

 not, it is true, set any definite lower limit of depth to this zone. That would doubtless 

 vary with different species; likewise with the abruptness of descent of the sea floor. e 

 But even in this loose and inexact sense it is certainly a convenient term by which to 

 designate such waters as those dredged by us with the Phalarope and Blue Wing. As 

 a useful alternative term "infratidal" might be employed, though there is no implication 

 in this word of a lower limit of depth any more than in "sublittoral." 



A converse type of distribution to that just discussed is exhibited by certain other 

 forms which were dredged predominantly at depths of 10 fathoms or more. A few of 

 the commoner of such species are: Tubularia couthouyi, Strongylocentrotus droebachi- 



<• E. g., by Petersen and by Ortmann. The littoral zone of Edward Forbes, on the other hand, extended from high-water 

 mark to a depth of s fathoms. To make confusion worse confounded, we have the "littoral " fauna and flora of land zoology and 

 botany, which are not marine at all. 



" The substitution of this term is favored by Dr. Stejneger in a letter to one of the authors. 



« A circular letter of inquiry which we sent to eight leading American ecologists revealed a surprising lack of unanimity in 

 the use of all these terms. 



<* It is in this latter sense that the term is employed in the botanical section of this report (cf. p. 453, 454). 



' Perhaps it would ordinarily be limited, in Buzzards Bay and Vineyard Sound, by the 5-fathom line, but this would not 

 always be true. 



