ANNULOIDA

(Lat.), n.n.pl. A?n(a8n)-nu%(nu)-lo-i(e)/das, Sy Echinozoa. A subkingdom of invertebrates proposed by Huxley; distinguished from the Protozoa and the Coelenterata by having a distinct nervous system and an alimentary canal entirely shut off from the general cavity of the body, and from the Annulosa by the absence of distinct segmentation. They have a_water-vascular (aquiferous) system of canals, usually communicating with the exterior, filled with water, and sometimes a true vascular system. In none of them is the adult provided with bilaterally disposed succe ive pairs of appendages, They comprise the cla es Echinoderm at a and Scolecid a. [B, 28; L, 147.]