EXPORT ON THE DEEP-SEA DEPOSITS. 
265 
of the order are quite absent. The valves of Scalpellum, Balanus, etc., are frequently 
met with, but never in any abundance. The most constant remains are the valves of 
certain species of Ostracoda which secrete thick calcareous shells. These animals 
evidently lived on the bottom where their shells are found, and, although limited in 
numbers, extend to the most profound depths. It is seldom that any specimen of a 
Fig. 26. — Krithe producta,'Rxa.&j. Fig. 27. — Cythere dictyon, Brady. 
calcareous ooze from the deep sea is examined without several of the valves of these 
organisms being observed, Krithe producta and three species of Cythere are almost 
universally present in deep-sea deposits.^ 
Echinodermata . — Representatives of the various orders of Echinoderms are wide- 
spread over the sea-bottom at all depths, and one would expect to find their remains 
somewhat abundant in the deposits now forming in the ocean ; like the Crustacea, how- 
ever, the areolar nature of the shells seems to determine the removal of the hard parts in 
solution shortly after the death of the animal. It is seldom that a large sample of 
Globigerina Ooze or Pteropod Ooze can be examined without some fragments of Echini 
spines being observed, but it is the exception to meet with any other remains in the 
deep-sea deposits. In Coral Muds and Sands and other deposits near land, fragments 
of the shells and spines of Echini, Starfish, and Ophiurids are frequently present, and 
in moderate depths fragments of Crinoids have been noticed,^ 
Polyzoa . — There are many species of Polyzoa or Bryozoa which secrete carbonate 
of lime, and in some localities the fragments of these compound organisms make up a 
large part, if not the greater part, of the deposits, as, for instance, in 110 to 150 fathoms 
ofiT Tristan da Cunha, and in 50 to 300 fathoms off Marion and Prince Edward Islands. 
In both shallow and deep water fragments of Polyzoa are nearly always to be observed, 
but in the pelagic deposits they make up but an insignificant part of the carbonate of 
lime present.^ 
1 See Hoek, Report on the Cirripedia, Zool. Chall. Exp., pt. 25 ; Brady, Report on the Ostracoda, Zool. Chalk Exp., 
pt. 3. 
2 See Agassiz, Report on the Echinoidea, Zool. Chall. Exp., pt. 9 ; Sladen, Report on the Asteroidea, Zool. Chall. 
Exp., pt. 51 ; Lyman, Report on the Ophiuroidea, Zool. Chall. Exp., pt. 14 ; Carpenter, Report on the Crinoidea, Zool. 
Chall. Exp., pts. 32 and 60. 
® See Busk, Report on the_Polyzoa, Zool. Chall. Exp., pts. 30 and 50 ; Waters, Zool. Chall. Exp., pt. 79. 
(deep-sea deposits chall. exp. — 1891.) 31 
