150 BULLETIN OF THE BUREAU OF FISHERIES. 
Callocardia morrhuana (chart 
PAO) «= sn siesta aaeee Peete Sek Si Prince Edward Island to Florida. 
Petricola pholadiformis (chart 
8B PARES 54 te Bh, cari aa Prince Edward Island to Nicaragua. 
Tagelus gibbus (chart 148). .....Cape Cod to Brazil. 
Tellina tenera (chart 149)...... Prince Edward Island to Barbados. 
Macoma tenta (chart 150)..... Cape Cod to Haiti. 
Cumingia tellinoides (chart 152) Cape Cod to south Florida. 
Mulinia lateralis (chart 154). ...New Brunswick to Texas. 
Lyonsia hyalina (chart 157). ...Nova Scotia to Texas. 
Corbula contracta (chart 159). ..Cape Cod to Jamaica. 
Of approximately equal range north and south (7). 
Solemya velum (chart 136).....Nova Scotia to North Carolina. 
Astarte undata (chart 138)...... Gulf of St. Lawrence to Cape Hatteras. 
Astarte castanea (chart 139)... .Nova Scotia to New Jersey and off Hatteras (deep). 
Ensis directus (chart 151)...... Labrador to Texas. 
Cochlodesma leanum (chart 156) Nova Scotia to Hatteras. 
Clidiophora gouldiana (chart 
Joc) Oe Re SG ror SS aS Nova Scotia to New Jersey (North Carolina ?). 
Mya arenaria (chart 160)........Arctic Sea to Miami, Fla. 
It will be seen that exactly one-third of these species have been listed as predomi- 
nantly northern, while very nearly one-half are to be regarded as southern. The seven 
remaining species are not assignable to either division. 
The following species are recorded from our dredgings, but were not taken frequently 
enough to warrant us in plotting their distributions: 
Pecten islandicus. Tellina tenella. 
Modiolus demissus. Siliqua costata. 
Modiolaria levigata. Thracia septentrionalis. 
Nucula delphinodonta. Periploma papyracea. 
Astarte quadrans. Saxicava arctica. 
Aligena elevata. Cyrtodaria siliqua. 
Phacoides filosus. Pholas costata. 
Cardium ciliatum. Zirphea crispata. 
Gemma gemma. Teredo navalis. 
Most of these species appear to be actually rare within the region. Several of them, 
on the contrary (Modiolus demissus, Gemma gemma, Teredo navalis) are extremely 
abundant in their proper habitats, though rarely taken with the dredge. 
Il, AMPHINEURA. 
Of the Amphineura, or chitons, only two species are found in this region. One of 
these, Trachydermon ruber, is quite rare locally. We have met with it but twice in 
dredging, only a single specimen having been taken on each occasion. Both were 
found near the lower end of Buzzards Bay. ‘This species is essentially a northern one, 
being said to range from the Arctic Sea to New York. The other, Chetopleura apiculata, 
is scattered pretty generally throughout the eastern half of Vineyard Sound and along 
the shores of Buzzards Bay (chart 161). Its scarcity in the western portion of the Sound 
and its apparent absence from the deeper waters of the Bay are perhaps due chiefly to 
the character of the bottom. As is well known, the chitons adhere to solid objects, such 
