i895. RESULTS OF '^ CHALLENGER" EXPEDITION. 51 



classification adopted b}' Malmgren, the main features of which 

 had been tested by anatomical inquiry, was fairly satisfactory, though 

 the genera may require reduction. No links connecting the Anne- 

 lida to other groups were found, so that the present boundaries 

 remain. Into all the novelties it is impossible to enter, but such 

 striking facts as the sexual differences of certain Polynoidae, the 

 curious modification that takes place in the ventral division of the 

 foot in others — reducing the ventral bristles to one, and the further 

 addition to our knowledge of commensal forms, are worthy of mention. 

 Our knowledge of the visual organs of the Annelida was extended 

 in a noteworthy manner, especially by the discovery of large 

 complex eyes in the Phyllodocidas, such a condition having hitherto 

 been known only in the Alciopidse, Ramose types of marine 

 annelids, again, were unknown till the " Challenger " dredged a 

 hexactinellid sponge off the Philippines containing a complexly- 

 branched Syllis, an animal, indeed, which had a furor for budding 

 and extending into all the ramifications of the canal-system of the 

 sponge. A single example thus takes the place of a colony, and the 

 reproductive elements are useful chiefiy for spreading the species on 

 fresh sites. Remarkable members of the Chloraemidae from the 

 abysses of the Atlantic and Pacific, e.g., Trophonia wyvillei and 

 Buskiella, show that closely allied forms range from tide-marks to 

 great depths. The tubes of many of the sedentary forms were no less 

 striking than the animals themselves — for the beauty and ingenuity 

 of their formation. 



The Expedition showed that some species were cosmopolitan. A 

 large number occurred in the North Atlantic, and did not range to 

 other areas, yet this may be due to the more or less unexplored 

 condition of these areas. Thus the Amphinomidas (with a single 

 exception) are absent from the north-east part of the area, while 

 they abound in the south-western; while the Euphrosynidae appear 

 between tide-marks in the southern parts, but are limited to the 

 deeper water in the northern. The centres for specimens in the 

 South Atlantic were Brazil and the Cape, and the peculiar types 

 belonged chiefly to the Polynoidae and Terebellidae, the latter 

 especially abounding in the mud of Kerguelen in the South-Indian 

 area. The Australian region had for the most part unique types, 

 comparatively few of which ranged into other areas. The Philippine 

 or Japanese region was specially rich in novelties. The Expedition, 

 further, emphasised the fact that in the warmer areas the Amphino- 

 midoe, the Eunicidae and the Alciopidae were specially abundant, and 

 that the distribution of most of the families was world-wide, e.g., the 

 Aphroditidae of which one genus, LcBtmonice, occurs in the deeps of the 

 great oceans and ranges also to the British Isles. 



The greater number of species appear to frequent shallow water 

 (probably because this had been most effectively worked), yet 

 annelids are found in the deepest dredgings, such as 2,500 and 3,125 



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