98 BULLETIN OF THE BUREAU OF FISHERIES. 
These charts nearly all agree in showing the paucity of ccelenterate life in Buzzards 
Bay, to which reference has already been made. In fact, but two species (Eudendriwm 
ramosum and Astrangia dane) appear to be of anything like as general occurrence in 
the Bay as in the Sound. ‘Two species among those charted were not recorded from a 
single station in the former body of water, while some of the others are confined within 
its limits to the extreme lower end or to the immediate neighborhood of land. This 
last condition is found to obtain in the case of many species belonging to nearly every 
group which do not thrive upon muddy bottoms, and their distribution is readily 
explainable by reference to this fact. Hydroids, as is well known, depend for support 
upon a solid substratum, such as is afforded by stones or dead shells, and their frequent 
occurrence upon bottoms which are listed as of pure sand is doubtless made possible 
by the presence of shells. Where such solid objects occur in the Bay, however, they 
are commonly more or less covered by soft mud. Nevertheless, at least one species of 
hydroid, Eudendrium ramosum, has established itself in considerable abundance on 
the floor of Buzzards Bay, a fact which is difficult to explain when we consider the 
almost total absence there of Pennaria trarella, a species having a quite similar mode of 
life, and one which is abundant throughout the Sound. 
Of considerable interest is the scarcity of Hydractinia echinata over the whole central 
area of Buzzards Bay. ‘That this is not due to the scarcity within this area of the her- 
mit crabs upon whose shells Hydractinia commonly dwells may be seen by reference to 
charts 109, 111 and 112, from which it is evident that the three commonest local Paguri 
are present throughout the entire Bay. It was at first thought possible that the non- 
appearance of this hydroid in the records of the Fish Hawk for Buzzards Bay might 
have been due to the failure of those responsible for the latter series of stations to 
include it when listing the contents of the dredge. That this is not a satisfactory expla- 
nation was shown in the course of some supplementary dredgings made during the 
summer of 1909. Hermit crabs (P. longicarpus and P. annulipes) were taken at 16 of 
the former Fish Hawk stations, but in only a single instance was Hydractimia met 
with, though Podocoryne was noted three times. 
Several of the hydroids, particularly Tubularia couthouyt and Thuraria argentea, 
appear to show a marked preference for the eastern half of Vineyard Sound, where the 
bottom is in large measure stony. The distribution of Odelia geniculata is probably 
dependent upon that of certain alge, to which it is generally found attached. Its 
abundance in the vicinity of Gay Head probably stands in direct relation to the occur- 
rence there of large numbers of the kelps (Laminaria), upon which it frequently grows. 
At least two very instructive cases are to be noted among the species charted, 
which appear to be intelligible only by reference to temperature conditions. We refer 
to the two actinians, Alcyonium carneum and Astrangia dane. ‘The former was found 
to be confined to the western end of Vineyard Sound and the extreme lower end of 
Buzzards Bay. It was not surprising, therefore, to meet with this species at several 
of the Crab Ledge stations. The case is quite comparable with that of the sponge, 
Polymastia robusta, referred to on page 94, and with many others which will be considered 
later. The limits of distribution for this species, so far as known, are: Rhode Island 
a These supplementary dredgings, however, added several species to the fauna of the Bay, so far as recorded by us. These 
were Clytia cylindrica, Pennaria tiarella (which is doubtless common enough in shallow waters near shore), Podocoryne carnea; 
and Schizotricha tenella. While none of these were taken with sufficient frequency to affect seriously our conception of the coelen- 
terate fauna of the Bay, they point to the probability of considerable gaps in our original records for this group. 
