148 BULLETIN OE THE 



mulated that we made satisfactory hauls on our Southern lines. What 

 was obtained seemed to be a scanty northern extension of thfe fauna of 

 the Caribbean Sea and of the Gulf of Mexico between the 100 and 350 

 fathom lines. It was not until we trawled on the steep slope of the 

 Gulf Stream plateau south of Cape Hatteras, where the bottom was fine 

 mud and Globigerina ooze, that we made a rich harvest again, in striking 

 contrast to the poor hauls along the well-swept rocky or hard bottom of 

 the Gulf Stream to the southward. Along the western edge of the Gulf 

 Stream we came upon several patches of the modern green-sand forma- 

 tion, where the bottom was entirely composed of perfectly clean dead 

 Globigerinse. Although Pteropods were very common at the surface all 

 the way from Charleston to Cape Hatteras, they were only rarely brought 

 up dead from the bottom ; but when the steep slope south of Hatteras 

 was reached they again assumed a prominent part in the composition of 

 the bottom mud. 



AVhile running the line parallel to the coast from off Charleston to 

 Cape Hatteras, we came twice upon localities where the sounding cup 

 brought up nothing but clean Globigerinse, the bottom consisting en- 

 tirely of the modern green-sand to which Bailey and Pourtales had 

 already called attention as forming off shore on the Atlantic coast of the 

 United States. The rapid changes in the character of the mud, as we 

 increase both our distance from shore and the depth, are well shown in 

 the nature of the bottom of the different depths along the short, steep 

 line forming the northern slope of the Gulf Stream plateau traced by the 

 " Blake " from Charleston to south of Cape Hatteras. We very rapidly 

 pass from the comparatively coarse mud to fine and finer ooze, which 

 becomes an impalpable silt in the deeper water beyond 1,000 or 2,000 

 fathoms, assuming at the same time gradually a lighter color. 



Among the Tunicates I may mention two new species of Salpse, one 

 of which is interesting, its chain occupying an intermediate position 

 between that of Salpa pinnata and the ordinary Salpa chain of S. zo- 

 naria or S. Cabotti of our coast. The solitary individuals are gigantic 

 specimens, measuring no less than twelve inches in length. This solitary 

 form is closely allied to S. maxima, but differs from it in the number 

 and arrangement of the muscular bands. The chains grow to a great 

 length, some of them measuring more than ten feet in length and as 

 much as nine inches in breadth. The zooids are arranged as in S. pin- 

 nata, side by side in a single row, extending vertically across the whole 

 width of the chain, and forming a thin ribbon, which when doating is 

 usually shghtly coiled like a tape. The zooids of the chain resemble 



