INVERTEBEATE ANIMALS. 45 



Ctodftlj CaMc Case. 



Tlie Mark H indicates specimens or other il'ustrations exhibited in. the Cases. 



Sub-kingdom ANNULOIDA. 



Animals possessing a distinct nervous system, a 

 water vascular system, and a food canal shut 

 off from the body cavity : body of the adult 

 having its somites (merosomes) disposed 

 radially. 



As the principal departure from the ordinary method 

 of arrangement occurs at this point, it may be proper 

 for the Writer to mention, by way of explanation, that 

 he cannot bring himself to regard the high development 

 of special organs in the Cephalopoda, due probably to 

 the absence of morphological obstructions, as in any wise 

 equivalent in importance even to the first prefigurements 

 of the great annulose type ; in which many somites, 

 each in itself an individual of a lower grade, unite 

 as constituents, first of a type with an exo-skeleton 

 (Arthropoda), subsequently of a type with an eudo- 

 skeleton (Vertebrata), by degrees consigning their 

 combined energies to be under the superintendence, 

 first of a cephalic ganglion, at length of a brain. — 

 H. H. H. 



Class ECHINODERMATA. 

 Ixlvoj, the hedgehog ; Ssp/^a, the skin. 



The general arrangement of the groups in this Class 

 is in accordance with the classification adopted 

 by MM. DujARDiN and Hupe, in " Histoire 

 Naturelle des Zoophytes Echinodermes.^' (Suites a 

 Buffon. Paris, 1862.) 



