BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 119 
although we have encountered these tubes (or rather short segments of tubes) at 198 
stations throughout Vineyard Sound and Buzzards Bay, we have not a single record 
of having taken even the anterior portion of the worm itself in the course of our dredg- 
ing. Our records for Chetopierus pergamentaceus, Clymenella torquata, Melinna macu- 
lata, and the two species of Pista likewise relate almost exclusively to tubes; although 
the first two of these species, at least, may be readily collected by digging in shallow 
water. It is highly probable also that some small and inconspicuous species were 
pretty constantly lost or overlooked in the process of washing large quantities of mud 
or sand, particularly as we were seldom assisted in the field by anyone having an ade- 
quate knowledge of this group.” 
Mistakes due to the actual confusion of one species with another in the field records 
are probably particularly infrequent for the annelids, in as much as nearly all of the 
specimens were reserved for identification by Dr. Moore. ‘The one known case in which 
a certain degree of confusion exists is that of the small tube-dwelling worms of the genus 
Spirorbis. It was not at first realized that several species of closely similar appearance 
existed within the limits of the region dredged, and for this reason it was not thought 
necessary to save samples from every dredge haul. It has consequently been found 
necessary to list a considerable proportion of our specimens merely as “‘.Spirorbis sp. 
undetermined;’’ and it has not seemed worth while to present the distribution charts 
for any members of the genus, although at least one of these (S. tubejormis) is known 
to have been taken at more than tro stations. 
On the average, 4.3 species of Annulata were recorded for each of the Survey dredge 
hauls. The species found to have the most general distribution was Hydroides dianthus, 
which was taken at 223 of the 458 stations. Those encountered so frequently as to be 
taken at one-fourth of the total number of stations were: 
Hydroides dianthus (223). 
Diopatra cuprea (198). 
Nereis pelagica (192). 
Harmothoé imbricata (189). 
Lepidonotus squamatus (165). 
As might have been readily inferred from the habits of this group of organisms, the 
character of the bottom was found to be the dominant influence in determining their dis- 
tribution. Now, we have seen that the bottom of Buzzards Bay, as a whole, is muddy, 
whereas most portions of Vineyard Sound, however much they differ in other respects, 
agree in the scarcity of mud. Accordingly we find it possible to divide the majority of 
the annelids from the Survey dredgings into predominantly Bay-dwelling and predom- 
inantly Sound-dwelling forms. 
As judged by our dredging records, members of this phylum are encountered with 
considerably greater frequency in Buzzards Bay than in Vineyard Sound. The average 
number of species taken per dredge haul for each body of water and for each vessel may 
be tabulated as follows: 
Vineyard Sound: 
Paneeramy eomcatiomnss O29 6 ed Lo ea intranets 6 avg 
Phalakoperstations iy si) vs... 251. iain bras « 95 does stars ares eee aie 2. « 4.6 
Buzzards Bay: 
HSH Lau RASt TOTS sears wicie ais < oon siscedsrciehtase ia ala baa EER eerie eae Se 6. 2 
Phalare passe paeionys crs). ce 3: av eee ie, Oss rae a\pPn reel elehdein a WRENS Oa TERT oe 08-03 4.6 
@ To obtain satisfactory results, portions of the bottom material should be covered with sea water and left standing in dishes 
for some hours. 
b This statement is in no way inconsistent with the fact that the total number of species recorded for the Sound as a whole 
is considerably greater than that recorded for the Bay (p. 80). 
