HYDROIDS AND JELLY-FISH 45 



in all the Hydroids ; in many species they remain attached to the 

 colony, looking like little umbrellas fastened by their ferrules 

 to the colony, and produce their eggs and ciliated planulas in that 

 situation. These permanently attached generative buds gener- 

 ally lose to a greater or less extent the umbrella-like form char- 

 acteristic of the free-swimming medusas. On almost any shore, 

 specimens of the dead and dried polyparies of various Hydroids, 

 such as the " Squirrel's-tail," the " Sea-cypress," the " Bottle- 

 brush," the " Sea-fir," and the " Sea-beard " or " Lobster's-horn," 

 to quote the popular names expressive of their general appear- 

 ance, are to be found. 



The graceful, branching forms of the colonies, varying in the 

 most wonderful degree in different species, the delicate, varied 

 tints of the tentacle-crowned polyps, and their extraordinary life- 

 history, make the Hydroida most deeply interesting forms of 

 life. To quote Professor Hincks, who devoted many years of his 

 life to the closest study of these remarkable organisms, " there 

 must always be a certain fascination in a history which tells us of 

 animals composed of multitudes of individuals living an associated 

 life, and so combining as to produce the most graceful plant- 

 like structures vegetating like a tree putting forth thousands 

 of polyps, like leaves, each a provider for the commonwealth 

 putting forth also a company of buds, charged with the perpetua- 

 tion of the species, ripening in transparent urns and scattering 

 their winged seeds broadcast, or sent forth, moulded and painted 

 by the highest art, like fairy emigrant ships freighted with young 

 life, to colonise distant seas. And these are the simple facts of 

 Nature." 1 



The Hydrocorallina resemble the Reef Corals in forming a 

 calcareous skeleton, and indeed were at one time supposed to 

 belong to the same class. Thanks, however, to the researches of 

 Professor L. Agassiz, Professor H. N. Moseley, and Professor 

 Hickson, their true character and life-history has been worked 

 out and proves them to belong to the Hydroids. The Hydro- 

 corallines are divided into two families, called respectively Milli- 

 pores and Stylasters. The Millipores form massive laminate or 

 branched growths of a strong coral-like character, dotted over 

 with minute pores, and having within a tubular structure crossed 



1 "Quarterly Journal of Science," Vol. II., No. 7, P- 



