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Show 1897.] ON THE DISTRIBUTION OF MARINE MAMMALS. 349 Dr. Michaelsen1 has termed the "Eitrichterblase." Attached to this is the egg-sac or Eeceptaculum ovorum. The interior of this egg-sac is divided by trabeculae into many compartments, in the interior of which are eggs in all stages of development surrounded by other germinal cells ; the structure in fact is precisely like that which is now known to characterize so many, perhaps all the Eudrilidae. I could not, however, detect a striated membrane surrounding the ripe ova such as that which I have described in Hyperiodrilus2. The " Eitrichterblase" communicates on the one hand with the short and muscular oviduct which opens on to the exterior in the fourteenth segment as usual, and on the other with a delicate tube which ends anteriorly in a swollen oval extremity. This latter sac lodges the ovary, which is thus, as in so many Eudrilids, in. direct communication with the efferent apparatus. It will be observed from the description of the egg-apparatus of the present earthworm, that though generally like that of the more highly developed Eudrilidae, it differs in detail from that of any other genus. As it has been hitherto customary to mark the genera mainly by the differences in this structure, I feel justified in making a new genus for this species from Lagos. 4. On the Distribution of Marine Mammals. By P. L. S C L A T E R , M.A., Ph.D., F.R.S., Secretary to the Society. [Received March 8, 1897.] (Plate XXIV.) CONTENTS. I. Introductory Remarks, p. 349. II. Distributidnof Pinnipeds, p. 350. III. „ of Sirenians, p. 351. IV. ,, of Cetaceans, p. 352. V. Division of the Marine Area of the Globe into Sea-regions, p. 353. VI. The North Atlantic Sea-region, or Arctatlantis, p. 353. VII. The Mid-Atlantic Sea-region, or Mesatlantis, p. 354. VIII. The Indian Sea-region, or Indopelagia, p. 355. The North Pacific Sea-region, or Arctirenia, p. 355. The Mid-Pacific Sea-region, or Mesirenia, p. 356. XI. The South Polar Sea-region, or Notopelagia, p. 356. XII. Conclusions, p. 357. IX. X. I. Introductory Remarks. Most of the recent writers on Geographical Distribution have confined their attention to terrestrial mammals, or at any rate have but casually alluded to the marine groups of that Class. On the present occasion I wish to call your attention to some of the 1 W . Michaelsen, " Oligochseten des naturhistorischen Museums in Hamburg," Jb. Harnb. Wiss. Anst. viii. 2 F. E. Beddard, " On the Structure of two new Genera of Earth worms belonging to the Eudrilidtje and some Remarks on Nemertodrilus," Quart. Journ. Micr. Sci. xxxii. n. a. |