[27] ALBATROSS EXPLORATIONS. 529 



enumerate 34 species from between 2,000 and 3,000 fathoms, which is a 

 much greater number than had previously been recorded from such 

 depths in the North Athiutic, 



The species and varieties already described as new from the 1883 

 collections are 76, as follows: Cephalopoda, 4; Gastropoda, 58 ; Soleno- 

 concha, 4; Lamellibranchiata, 10. The total number of species of Mol- 

 lusca added to the fauna of this region by the Fish Commission dredg- 

 ings since 1880 is over 275. 



The diiferent groups of Mollu sea differ greatly in the relative propor- 

 tion of deep and shallow water species, as shown by the following tables. 

 Thus the deep-water Cephalopods are 23, against 4 shallow-water and 

 surface species. The Gastropods exclusively deep water are 166, 

 against 38 of shallow -water origin. The shallow- water Lamellibranchs, 

 however, seem to have a much greater tendency to range into deep 

 water, for of these there are but 68 deep-water species and varieties, as- 

 sociated with 46 shallow- water ones. 



TUNICATA, 



On the upper part of the Gulf Stream slope, at the depths of about 65 

 to 125 fathoms, in localities where the bottom is of compact sand and 

 gravel, it is often well covered, with various sponges, hydroids {Tubu- 

 laria, Cladocarpus, &c.), and large, rough groups of a coarsely wrinkled 

 ascidian, which appears to be identical with Cynthia partita Stimpson. 

 This species occurs abundantly in shallow water on stones, piles, &c., 

 from IsTorth Carolina to Vineyard Sound, often forming, in such situa- 

 tions, large, irregular clusters. A few other species, not yet studied, 

 also occur, though less commonly, on the hard bottoms in 100 to 125 

 fathoms. At the northern stations, otf Nova Scotia, where the bottom 

 is often stony, many of the well-known northern forms occur, such as 

 Boltenia Bolteni, Ascidia complanata, Cynthia pyriformis, &c. In the 

 deeper waters, where the bottom is usually of soft mud and sand, or ooze, 

 ascidians are not very common, though several undetermined species of 

 Molgula and allied forms have been taken. One species of Molgula, 

 which was taken in 1,608 fathoms, is about an inch in diameter, soft, 

 flattened, and covered with a thick coat of foraminifera. 



The most interesting ascidian taken by us is a new species of the 

 curious, long-stemmed genus, Culeolus, first discovered by the "Chal- 

 lenger." It is peculiar to deep water, and a species very closely allied 

 to our own was dredged by the " Challenger " off the coast of Japan. 1 

 have named our specie? Cni^i.lvs lanneri (figs. 144, 145, a. ft.),* in honor 

 of our accomplished commander. 



* Culeolus Tanneri Verrill, sp. nov. Stem long, slender, somewhat decreasing in size 

 from the base to the summit. Body irregularly pear-shaped, the lower end tapering 

 to a conical form, where it joins the stem, while the stem itself can be seen extending 

 upward about 15 to 20'"'i^ along the dorsal margin, where it forms, for that dis- 

 tance, a rounded midrib terminating in a prominence in one specimen and at a de • 

 H. Mis. 67 34 



