Gi6 SUMMARY OF CURRENT RESEARCHES RELATING TO 



' Lightning,' ' Porcupine,' ' Knight Errant,' and ' Triton.' In all, 42 new 

 genera and 196 new species are described. The collection made by the 

 'Challenger' is stated to afford a fair representation of the general 

 character of the Asterid fauna of the globe, so far as known. A large 

 number of abyssal forms have been found and their discovery may be 

 said to have oj)ened a new chapter in the history of the Asteroidea. 

 The archaic characters of a number of the deep-sea forms are highly 

 remarkable, and furnish not only a confirmation of the validity of the 

 classification now adopted, but also give an important clue to the 

 systematic j)osition of many members of the class. 



Mr. Sladen does not take the same view of the value of the 

 l)edicellari9e as does Prof. Perrier, fur he considers that the most archaic 

 forms have the sim.pler and less complex pedicellarise, nor have these organs 

 the more subordinate systematic value which the French naturalist also 

 ascribes to them. The more valuable bases for classification are to be 

 sought for in (1) the adaptation of the organism to subserve the functions 

 of respiration and excretion, (2) the character of the ambulacjal skeleton, 

 and (u) of the ambital skeleton. The respiratory j)apula3 may be 

 distributed over the whole body or confined to more limited areas, and 

 these may be called respectively the Adetopneusia and the Steno- 

 pneusia. There are two modes of growth in the ambulacral skeleton ; 

 the production of the parts may be accelerated iu relation to the growth 

 of the starfish, or be retarded, or proceed pari passi ; here the terms 

 Leptostroteria and Eurystroteria come into use. 



The third chief morphological point is the character of the marginal 

 plates ; these may develope rapidly, and form an important characteristic 

 throughout life, as in the Phanerozonia, or they may be hidden and 

 insignificant as in the Cryptozonia. 



The three divisions to which these three sets of two names apply are 

 essentially equivalent, and the groups are regarded by the author as 

 natural orders in the strictest sense of the term. We have then the 

 Phanerozonia (Stenopneusia ; Eurystroteria) as the first order of the 

 sub-class Euasteroidea of the class Asteridea ; the families included 

 therein are the Archasteridse, of which the Pararchasterinse, Pluto- 

 nasterineee, and Pseudarchasterinse are new; the Porcellanasteridas, 

 described in 1883 from ' Challenger ' specimens ; the Astropectinidse ; 

 the Pentagonasteridas ; the Antheneidge ; the Pentacerotidae ; the 

 G-ymnasteridse ; and the Asterinidae. 



The second order or Cryptozonia ("Adetopneusia; Leptostroteria) 

 contain the Linckiidge, the new iamily Zoroasteridse, the Stichasteridte, 

 th3 Solasteridse, the Pterasterid*, Echinasteridse, Heliasteridse, Pedi- 

 cellasteridse, Asteriidae, and Brisingidse. A synopsis of the orders and 

 families is given. 



After describing the collection with great detail, Mr. Sladen gives a 

 list of stations at which Asteroids were collected, enumerating the 

 species found at each ; then follow tables showing the known bathy- 

 metrical range of the genera ; others which show the nature of the sea- 

 bottom ; and finally, there is a list of the known species of recent 

 Euasteroidea with the principal localities, the general geographical and 

 bathymetrical distribution, and the synonyms. The collection of Star- 

 fishes seems to be one of the most important of those made by the 

 ' Challenger.' 



