1 6 THE ANTHOZOA 



in Haimea and Hartea. Haeckel describes and figures the ovaries 

 of Monoxenia, but his account leaves much to be desired. 



GRADE B. SYNALCYONACEA. 



The Synalcyonacea are all colonial. The colony originates 

 from a mother zooid, which gives off hollow diverticula from its 

 base or from its lateral walls. From these diverticula buds are 

 formed, which grow into new zooids, and these again give off 

 diverticula. In this manner colonies of complex character are 

 formed. 



It is characteristic of the Synalcyonacea that buds are never 

 formed directly from the mother zooid, nor yet from the daughter 

 zooids ; they are always formed on tubular outgrowths of the 

 zooids, which have variously been named stolons, nutritive canals, 

 endodermic canals, etc. The name stolon is the least cumbrous, 

 but it has been applied not only to the canals but also to structures 

 composed of many canals united together, and its connotation is so 

 vague as to be misleading in the extreme. Throughout this 

 chapter the canals, lined by endoderm, which are given off as 

 diverticula from the coelentera of the zooids comprising a colony, 

 will be described as solenia, from the Greek o-wA^vtov, a little pipe 

 or conduit. The name stolon will be applied to the root-like 

 outgrowths by which many Synalcyonacea are fixed to stones, 

 corals, and other surfaces ; and following Hickson, the name will 

 be extended to the membranous expansions which are formed by 

 the union of many flattened, root-like outgrowths. 



It must be borne in mind that the cavities of Alcyonarian 

 zooids never communicate directly with one another, but always 

 by means of solenia ; these may be long, much branched, 

 anastomosing passages, or they may be so much reduced that the 

 zooids seem at first sight to be in direct communication. Closer 

 inspection, however, will always demonstrate the intervention of 

 solenia. 



The simplest form of budding, giving rise to the simplest 

 form of colony, is found in the genus Cornularia. In this genus 

 we find (on the authority of von Koch [54]) that the mother zooid 

 gives off from its base a simple, radiciform outgrowth or stolon, 

 which is composed of a single selenium. At a longer or shorter 

 distance from the mother zooid, a daughter zooid is formed as a 

 bud on the stolon. This gives off new stolons, and these branching 

 and anastomosing with one another may form a network, adhering 

 to stones, corals, Gorgonians, and other objects, from which zooids 

 arise at intervals. 



A further differentiation is found in the genus Clavularia. The 

 colony resembles Cornularia in form and in habit of growth, but 



