OF THE EOTATOBIA. 475 



Annulosa, under the name of Annuloida, the several families Annelida, Echi- 

 nodennata, Trematoda, Tui'bellaria, and Nematoidea, and in company with 

 these he would place the Eotifera. '' The terms of resemblance (to the An- 

 niiloida) are these : — 1. Bands of cilia, resembling and performing the func- 

 tions of the wheel organs, are found in Annelid, Echinoderm, and Trematode 

 larv^. 2. A water-vascular system, essentially similar to that of Eotifera, 

 is found in Monoecious Annelids, in Trematoda, in Turbellaria, in Echino- 

 derms, and perhaps in the Nematoidea, the Cestoidea, and the Nemertidae. 

 3. A similar condition of the nervous system is found in Turbellaria. 4. A 

 somewhat similarly armed gizzard is found in the Nemertidae ; and the pha- 

 r^mgeal annature of a Nereid larva may well be compared with that of 

 Albertia. 5. The intestine undergoes corresponding flexures in the Echino- 

 derm larvae. There are therefore no points of their organization in which 

 the Eotifera differ from the Annuloida ; and there is one very characteristic 

 circumstance, the presence of the water-vascular system, in which they agree 

 with them." 



Prof. Huxley next proceeds to inquire to which of the Annuloida the Eoti- 

 fera are most closely allied, and in so doing seeks for the fundamental types 

 of their organization by an ingenious mode of demonstration, adducing the 

 genera Stephanoceros, Philodina, Notommata, Brachionus, and Lacinidaria as 

 " the types of the great division of the Eotifera, and of which whatever is 

 tme will probably be found to be true of all the Eotifera." The result he 

 arrives at is, "that the Eotifera are organized upon the plan of an Annelid 

 larva, which loses its original symmetry by the unequal development of various 

 regions, and especially by that of the principal ciliated circlet or trochal 

 band." After some further remarks. Prof. Huxley adds — " I do not hesitate 

 to di'aw the conclusion " (which at first sounds somewhat starthng) " that 

 the Eotifera are the permanent forms of Echinoderm larvce, and hold the same 

 relation to the Echinoderms that the Hydi^aform Polypi hold to the Medusce, 

 or that Appendicidarice hold to the Ascidians. 



" The larva of Sipuncidus might be taken for one of the Eotifera ; that of 

 Ophiura is essentially similar to Stephanoceros ; that of Asterias resembles 

 Lacinidaria or Melicei^taJ^ 



Again, this talented naturalist believes that the Eotifera furnish the link 

 between the lower Echinoderms (which otherwise seem to lead nowhere) 

 and the Nemertidae and Nematoid worms, the Eotifera themselves forming 

 the lowest step of the Echinoderm di\dsion of the Annuloida, the proposed 

 subkiugdom of Cuvier's Eadiata. 



To elucidate his views. Prof. Huxley has appended to his essay a series of 

 diagrams sho^ving the essential correspondence between Eotifera and Annelid 

 or Echinoderm larvae. 



When Leydig wrote his memoir on the Eotatoria, he had the advantage of 

 seeing this contribution to their history by Prof. Huxley, and has remarked 

 in general terms, of the above views and their illustrations, that although the 

 ingenuity of the attempt to prove Eotatoria permanent larvae of Echinoderms 

 must be admitted, he is nevertheless unable to adopt the hypothesis of the 

 English observer, and must hold to his own idea of their Crustacean cha- 

 racter. 



The conclusion which it seems to us must be adopted is, that the Eotatoria 

 belong to the great group of the Eadiata known as Vermes, and stand in 

 more particular relation with those families Avhich make up the proposed di- 

 vision "Annuloida."' 



We must now add a few observations concerning the affinity exhibited by 

 the Eotatoria with the Ciliobrachiate Polypes or Bryozoa (a family of Polyzoa). 



