578 RECORD OF CURRENT RESEARCHES RELATING TO 



remains connected with the disk, and liere a new arm may be 

 developed. 



If these observations are not shown to be altogether misreported, 

 it will follow that there are in the Echinoderms two modes of meta- 

 genesis ; the one in which the so-called " larva " (^Pluteus, Bracliolaria, 

 &c.) functions as the nurse, and produces the Echinoderm by 

 internal gemmation, and the other, more rare, in which the spon- 

 taneously separated arm functions as a nurse and produces the sea- 

 star by external gemmation. 



These facts, in Professor Haeckel's opinion, largely confirm his 

 " corm theory." Dealing with Metschnikoff, who regards the arms 

 of the starfish as comparable to those of the cephalopod, he points 

 out that no cephalopod arm, no lizard's tail, no crab's limb, ever 

 produced a crab, cephalopod, or lizard ; and he further insists on the 

 high development of the locomotor apparatus of the Echinoderms. 

 To help forward the discussion, Haeckel proposes the name of Astro- 

 titliene (tlO-^vt] = a nurse) for the larval, and Astrocormus {Kopfj.6<; = 

 a colony) for the adult starfish ; the former is an unsegmented 

 bilaterally symmetrical person, the latter is made up of five parameres, 

 each of which is composed of two symmetrical antimeres ; in the adult 

 there is further to be distinguished the astrodiscus made up of five 

 congruent parameres (or five pairs of antimeres), and five astrolence 

 ((i)Xevr] = an arm), each of which is comjioscd of a pair of antimeres. 

 Traced in their developmental history, we see the multiplication of 

 the organism ; looked at genetically, we find the ancestor of the 

 astrotithcne in an unsegmented worm, most nearly allied to the 

 Rotatoria and the ciliated larva of the Annelides. 



The paper concludes with dividing the Echinoderms or Estrellee 

 into three primary classes (subphyla), and six classes. 



Subphylum 1. Protestrellce. Estrellce without internal centraliza- 

 tion, with complete morphological autonomy of the astrolente ; enteric 

 system consisting of a simple central intestine, and five (or more) 

 bifurcated special intestines. 1st class, Asterice. 



2. Anthestrellce. EstrcllcB with partial internal centralization ; 

 the proximal portion of tbe astrolense together with the whole of the 

 enteric system pass into the central astrodiscus ; no special intestines. 

 2nd class, Ophiiirce. 3rd class, Crinoida. 



3. Tliecestrellce. Estrello} with complete internal and external 

 centralization ; the five astrolenas pass completely into a single 

 spheroidal or tubular astrodiscus ; no special intestines. 4th class, 

 Blastoida. 5th class, Eclmiida. 6th class, Eolotkurice. 



Professor von Martens, whose descriptions of Echinoderms are 

 among the most valuable, has a note * on this subject. Speaking of 

 the great difficulties connected with Haeckel's hypothesis, he jwints out 

 that the arm of the sea-star contains all the representatives of all the 

 essential organs of the animal, and that we know of no other example of 

 a compound animal with a common mouth and all the other organs 

 separate, but that in all cases where a colony is formed by gemma- 



* ' Naturforscher,' xii. (1S79) p. 103. 



