1 INTRODUCTION. 



form. Those who have the opportunity will do well to 

 take up this line of investigation, which promises to yield 

 the most interesting results. The reproduction and de- 

 velopment of the Hydroida may be studied with great 

 facility in many of the littoral species of Coryne, Syncoryne, 

 Perigonimus and Tubularia. The ubiquitous Obelia geni- 

 culata may always be readily obtained in summer with its 

 capsules, within which the gonozooids may be watched 

 through all the stages of their development, and from 

 which they may be seen escaping in numbers. 



The larger and stouter species of Hydroida may be pre- 

 served by drying ; but even these lose much of their beauty 

 in the process. The Campanulariidte should be kept in 

 fluid*, as their calycles shrivel up when dried. The 

 Athecata generally must also be preserved in the same 

 way, as the polypites, which exhibit many varieties, afford 

 important characters ; and the mere polypary without them 

 is, in a large proportion of cases, useless for the purpose of 

 identification. Specimens kept in fluid retain much of 

 their original beauty, though of course the exquisite 

 colours that adorn many species are lost. 



But to appreciate fully the extreme loveliness of these 

 " animal-plants " they must be seen in life. A tuft of 

 Halecium or Eudendrium, the one laden with white, the 

 other with brilliantly tinted polypites, like blossoms on 

 some tropical tree, is a perfect marvel of beauty. The 

 unfolding of a mass of Plumularia taken from amongst the 

 miscellaneous contents of the dredge and thrown into a 

 bottle of clear sea-water, is a sight which, once seen, no 

 dredger will forget. A tree of Campanularia or Obelia, 



* The best methylated spirit is a good and convenient preservative fluid. 



