. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. 578 DEPTHS OF THE OCEAN individuals is the Sagittidae or Chaetognaths, which, along with copepoda, salpae, pteropoda, and radiolaria, everywhere constitute the bulk of the small pelagic organisms captured by our fine-meshed tow-nets. They are perfectly transparent, of slender build, and swift of motion. On the head are some bristle-like gripping appliances, and an elastic film-like rim, reminding
. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. 578 DEPTHS OF THE OCEAN individuals is the Sagittidae or Chaetognaths, which, along with copepoda, salpae, pteropoda, and radiolaria, everywhere constitute the bulk of the small pelagic organisms captured by our fine-meshed tow-nets. They are perfectly transparent, of slender build, and swift of motion. On the head are some bristle-like gripping appliances, and an elastic film-like rim, reminding one of the fin of a fish, runs along the body and the "tail" (see ). The Sagittidae comprise only a few genera, the most prolific in species being the genus Sagitta, which is represented in all oceans ; some of the species are very widely distributed, such as Sagitta hexaptera, S. serratoden- tata, S. bipunctata. In northern waters Krohnia kamata, Sagitta arctica, and Sagitta gigantea are characteristic forms, the last men- tioned having been taken by the " Michael Sars" in deep hauls in the Norwegian Sea, while Sagitta inflata is a form peculiar to warm waters. All these species are perfectly transparent, but during the Atlantic cruise we found specimens of a bright red colour, precisely like that of the pelagic Nemertines, belong- ing to Sagitta macrocephala and Eukrohnia fowleri; they were very abundant, and occurred, like the Nemertines, only in deep hauls. The very numerous families of higher worms, especially the Annelida, contribute very little to the pelagic fauna of the ocean. Among the best known is the genus Tomopteris, which has many beautiful surface forms, some of these (like T. septentrionalis) being boreal, some belonging to warm waters. In his narrative of the cruise of the " Valdivia," Chun tells us that nearly every haul from deep water in the Antarctic brought up beautiful specimens of Tomop- teris, as long as the finger
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1912
