. Narrative of a voyage to the Polar Sea during 1875-6 in ships ' Alert' and 'Discovery' [microform]. Alert (Ship); Discovery (Ship); Alerte (Navire); Discovery (Navire); Natural history; Sciences naturelles. m m 6;! 272 APPKNDIX. No. IX. from each of the cross joinings of whicli proceeds a spine- fasciculus bearinjy three or four spinelets. The wiiole dorsal surface of the animal is co/ered and concealed hy a mem- branous tissue supported above the body, like a tent-cloth, by the spinelets, to the tips of which it is attached. A hollow infradermal cavity is thus formed. Neither the anus
. Narrative of a voyage to the Polar Sea during 1875-6 in ships ' Alert' and 'Discovery' [microform]. Alert (Ship); Discovery (Ship); Alerte (Navire); Discovery (Navire); Natural history; Sciences naturelles. m m 6;! 272 APPKNDIX. No. IX. from each of the cross joinings of whicli proceeds a spine- fasciculus bearinjy three or four spinelets. The wiiole dorsal surface of the animal is co/ered and concealed hy a mem- branous tissue supported above the body, like a tent-cloth, by the spinelets, to the tips of which it is attached. A hollow infradermal cavity is thus formed. Neither the anus nor the madreporiform tubercle has any special aperture in this investing membrane; there is, however, a single large-sized opening, surrounded by a margin of spines, situated nearly over the dorso-central axis. In and out of this aperture Dr. Stimpson has observed currents of water passing, as in the cloaca of a Holothuria, from which fact he was led to regard the functions of the cavity as subservient to respiration.^ MM. Koren and Danielssen, however, have pointed out that this intermediate space between the double dorsal skin fuliils a further and more important purpose by becoming a chamber in which the development of the eggs and embryos takes place. ^ Although our knowledge of marsupiation in Echinoderms has recently been largely augmented by the additional in- stances which Sir Wyville Thomson records as occuiiing in species from southern sea •* it is most interesting to find so special an adaptation for the purpose in this truly Arctic asteroid. Two specimens only were obtained, being dredged by Mr. Hart in Dobbin Bay. They measure about 60 millims. in their greatest diameter. "Hi. Ophiuroidea. Ophioglypha Sarsii (Liitken), Lyman. Coll. Feilden: Floeberg Beach, 10 fms.; Discovery Bay, 25 fms.; Hayes Point. An Ophioglypha with mouth-shields shield-shaped, longer • Stimpson, 'Marine Invertelmita of Grand Mauan,' j). IT), iii .Smith- sonian Contribiilions, vol. v
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