402 Original Articles. [July, 



give an outline of the later views of the reproduction and development 

 of the Hydroida, and to supply the rationale of the facts, which have 

 been made the basis of so much ingenious theory. 



Before proceeding, however, to sketch the general characteristics 

 of the group under consideration, we wish to draw attention to the 

 very gradual accumulation of the facts on which our present theoretic 

 views rest, and the way in which we have been led on from point to 

 point by the observations of isolated students, until at length we have 

 attained a true conception of the entire history. In a series of papers 

 by various authors, extending over a considerable period of time, and 

 scattered through the Scientific Journals of Europe and America, are 

 to be found the successive steps by which we have advanced to the 

 point at which the true method of nature was recognized. Some 

 of these, of course, stand out from the crowd, as of pre-eminent 

 merit. But we are anxious to direct attention to the valuable co- 

 operation of those who have conscientiously put on record facts the 

 full significance of which they did not at the time appreciate, but 

 which have formed important links in the chain of evidence, by which 

 the truth has been finally established. In interpreting the reproduc- 

 tive history of the Hydroid Zoophytes, we have been indebted to the 

 suggestive observations of a large number of independent workers 

 for the hints which have guided us into the right track. Gradually a 

 series of facts has been accumulated, the significance of which was 

 only partially, if at all, appreciated at first, but which now supply the 

 basis of a complete and satisfactory theory. 



We would commend to those who may have a taste for Natural His- 

 tory, and fair qualifications and opportunities for the pursuit of it, but 

 who may not aspire to any very profound acquaintance with it in its 

 large extent, the careful and conscientious study of single life-histories, 

 as fraught with the highest interest in itself, and almost sure to yield 

 valuable results. In the history of zooj>hytology, there are names 

 which find an honourable place, and are inseparably connected with its 

 progress, by virtue of one or two observations of undoubted accuracy 

 and striking significance ; and amongst the many species of Hydroids, 

 which have not yet been followed through the various stages of their 

 development, there is still ample room for that quiet and patient in- 

 vestigation which is within the range of so many, which is so rich in 

 interest, and which has already done so much for the advancement of 

 the science. 



Animal-plant (Zoophyte) is not, after all, a bad popular name for 

 the fixed, compound, and arborescent beings, in which so many of 

 the characteristics of the two great kingdoms of nature are curiously 

 blended. The Zoophyte is an animal in which the vegetative life is 

 altogether predominant, which in its perfect state is commonly as sta- 

 tionary as the tree, and in a large proportion of cases imitates the 

 form and general arrangement of parts that belong to the plant. 

 The compound kinds which often attain a very large growth and are 

 so remarkable for their beauty, are the result, like the tree, of a 

 continued process of gemmation, bud after bud evolving itself and 

 helping to build up the vital structure according to the pattern of the 



