94 _ BULLETIN OF THE BUREAU OF FISHERIES. 
waters.¢ Herdman records 58 species from the Irish Sea, while Graeffe lists 45 species 
from the Gulf of Trieste. As implied in the foregoing discussion, it is likely that the 
Woods Hole list will be greatly extended by further investigations. 
Referring to our dredging records for this group, the distributions of certain forms, 
such as Cliona celata, Microciona prolifera, Tethya gravida, and Polymastia robusta, have 
probably been ascertained with a fair degree of accuracy. On the other hand, it is 
probable that some confusion occurs between the two species of Chalina, since specimens 
which were listed in the field records as C. arbuscula were in a number of cases subse- 
quently identified as C. oculata (see catalogue). For this reason a single chart has been 
prepared, which includes all the records for this genus. A similar confusion exists 
regarding the two species of Halichondria (H. panicea and H. caduca). And in addition 
to these equivocal records specimens belonging to entirely undetermined species of 
this genus are listed from about 20 of the regular dredging stations and were doubtless 
taken at many others. 
Under such circumstances little of a general nature can be said regarding the 
distribution of these animals in local waters. The species having the most general 
occurrence was Cliona celata Grant (=Spongia sulphurea Desor), which was recorded 
from 171 of the regular stations. This form seems to flourish nearly as well on one 
kind of bottom as another, though it is much less common in the western half of the 
Sound than in the eastern half.2 That its scarcity in the former region is not due to 
the lower summer temperature of the water there is rendered probable by the fact that 
this species has been reported by Lambe from Prince Edward Island, in the Gulf of 
St. Lawrence. It has not been taken by us, however, at Crab Ledge, where many of 
the typical cold-water species occur and many southern ones are lacking. 
Microciona prolijera is not uncommon in the Sound in the form of reddish incrus- 
tations on the surface of stones and shells. In Buzzards Bay, particularly in the inshore 
waters, it frequently grows up into the characteristic and beautiful arborescent form. 
A species of Grantia, which has been regarded as G. ciliata (Fabricius) by Verrill 
and others, is common on piles, and one or more species of the same genus (not improb- 
ably identical with the foregoing) were encountered at various points in dredging 
(chart 10). 
An interesting case of restricted distribution is exemplified in the case of Po/ymastia 
robusta, for which, however, no chart has been prepared, owing to the limited number of 
stations from which it was recorded. This readily recognizable species was taken by 
us a few times at the western entrance of Vineyard Sound and in the mouth of Buz- 
zards Bay; likewise at five of the seven regular stations of the survey at Crab Ledge. 
It is thus a representative of that colder water fauna which just enters the limits of our 
region. So far as we know, this species has not been listed from points farther south 
upon our coast than Marthas Vineyard, though ranging northward at least to the Gulf 
of St. Lawrence. 
Another case of definitely restricted distribution, for which, however, no explanation 
can be offered at present, is that of Tethya gravida. ‘This species, which was first described 
by Hyatt from specimens taken in Buzzards Bay, was encountered by us eight times, 
altis stated by the authors that ‘“‘the list is a very imperfect one, many common species not having been identified and 
recorded.” 
b The chart for this species likewise shows a considerable gap in the central region of the Bay, but specimens were later 
taken at several points in this area. 
