1897.] 



Olf THE DISTRIBTJTION Of MAEINE MAMSIAI/S. 



349 



Dr. Michaelsen " has termed tlie ''EitrichterbUise:' A ttached to this 

 is the egg-sac or Eeceptraculum ovorutn. The interior of this eg'g-sac 

 is divided by trabeculse into mau)' eompartmeuf-s, 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, per'naps all the Budrihdje. 

 I could not, however, detect a striated membrane surrounding the 

 ripe ova such as that which I have described in H)jperiodrilus-. 

 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 ovai-y, 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 Eudrilidfe, 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, ScLATKK, M.A., Ph.D., F.R.S,, Secretary to the 



Society. 



[Eeceired March 8, 1897.] 



(Plate XXIV.j 

 Contents. 



I. Introductory Eemarks, p. 349. 

 II. Distributionof 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. 

 IX. The North Pacific Sea-region, 

 or Arctirenia, p. .355. 

 X. The Mid-Pacific Sea-region, or 

 Mesireuia, p. 356. 

 XI. The South Polar Sea-regiou, or 

 Notopelagia, p. 35fi. 

 XII. Oonchisions, p. 357. 



I. Introductory RemarTcs. 



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 Ham- 

 burg," Jb. Hamb. Wiss. Anst. viii. 



- F. E. Beddai-d, " On the Structure of two new Genera of Earthworms belong- 

 ing to the Eudrilidse and some Eemarks on Nemertodrilus," Quart. Journ. 

 Micr. Sci. xxxii. n. b. 



