72 BULLETIN OF THE BUREAU OF FISHERIES. 
CIRRIPEDIA: PELECYPODA—Continued. 
Balanus eburneus (46). Venus mercenaria (52). 
AMPHIPODA: Callocardia morrhuana (80). 
Ptilocheirus pinguis (41). Tellina tenera (63). 
Unciola irrorata (32). Macoma tenta (30). 
DECAPODA: Ensis directus (64). 
Crago septemspinosus (50). Spisula solidissima (29). 
Pagurus longicarpus (83). Mulinia lateralis (60). 
Pagurus annulipes (44). Clidiophora gouldiana (80). 
Libinia emarginata (57). GASTROPODA: 
Cancer irroratus (43). Busycon canaliculatum (43). 
Neopanope texana sayi (43). Tritia trivittata (108). 
PELECYPODA: Anachis avara (67). 
Anomia simplex (74). Astyris lunata (48). 
Pecten gibbus borealis (57). Eupleura caudata (48). 
Arca transversa (78). Urosalpinx cinereus (29). 
Nucula proxima (74). Littorina litorea, shells only (48). 
Yoldia limatula (66). Crepidula fornicata (84). 
Crassinella mactracea (29). Crepidula plana (74). 
Cardium pinnulatum (79). Polynices duplicata (35). 
Levicardium mortoni (45). Polynices triseriata (41). 
Of the 50 species comprised in the above list only two“ are absent from that repre- 
senting the prevailing species dredged by the Fish Hawk in Buzzards Bay; while only 
7 species in the latter list are lacking from that for the muddy bottoms. The two groups 
of species are thus not far from identical. On the other hand, 13 of those in the list for 
muddy bottoms do not appear in either table for Vineyard Sound. Thirty-three of the 
species (66 per cent) are common to the list for sandy bottoms, while 34 species (68 per 
cent) are common to that for bottoms of gravel and stones. 
Comparing the lists for the three types of bottom, we find 13 species which appear 
only in that for bottoms of stones and gravel, an equal number which appear only in 
the list for muddy bottoms, while 6 are peculiar to the list for sandy bottoms. Of the 13 
prevalent mud-dwelling forms, all but 1 are annelids or mollusks. Of the 13 species 
peculiar to the list for gravelly and stony bottoms, 3 are hydroids and 3 are ascidians, the 
remainder being distributed through various phyla. The number of forms which are 
restricted to our list of prevalent species for bottoms of pure sand (free from mud on 
the one hand, and from stones and gravel on the other) isa very short one. This is due 
to the fact that the great majority of sand-dwelling species are not deterred by the pres- 
ence of a certain proportion of stones and gravel, while many of them are equally at 
home in sand which is somewhat muddy. In our classification, however, such bottoms 
have been included under ‘‘gravel and stones’’ and ‘‘mud,”’ respectively. At least two 
of the species listed are, nevertheless, pretty definitely restricted to bottoms of pure 
sand. These are the ‘“‘lady crab” (Ovalipes ocellatus) and the “‘sand dollar” (Echina- 
rachnius parma). 
In any consideration of such tables as the foregoing, it must be borne in mind that 
the fact of a species being restricted to one or another of the tables does not imply that 
it is absent from the other types of bottom, or subdivisions of the region. Indeed, it 
@ These two are contained in the Phalarope Buzzards Bay list. 
