BRYOZOA. 161 



2. Class.— BRYOZOA, Ehrenberg, 1832. 



The question whether these animals should rightly be known as Polyzoa or as 

 Bryozoa appears very intricate; although for the reasons given below Polyzoa 

 appears the more correct term, Bryozoa is here used for convenience. 



In 1830 J. V. Thompson published a paper "on Polyzoa, a new animal dis- 

 covered as an inhabitant of some zoophytes, with a description of the newly 

 instituted genera .... and three species." 



In this paper he uses Pohjzoa as a singular feminine designation of the soft parts 

 of the animal, in parallelism with Hydra, Actinia, Ascidia, Zoantha, so that it has an 

 equal value with these words, and he intimates that it may be a " new type of 

 Mollusca Acejrfiala." He, moreover, establishes certain genera, basing them on the 

 hard parts of the animal. Thus he writes, " Although the animals of Serial aria have 

 not yet been observed, yet, from . . . , there can hardly be a doubt but they 

 are the habitations of Polyzose, and not of Hydras, and consequently would find place 

 in our system next Vesicular ia ." 



The first question seems, therefore, to be whether the word so used can be 

 regarded as a zoological or an anatomical term ; whether it can be looked on as 

 defining a class of animals, or merely as a structural name for the contents of their 

 zoaria; whether, in fact, Polyzose meant a natural zoological group of animals, or 

 simply described their soft parts anatomically ; that is, whether Thompson 

 regarded the hard parts as skeletal or domiciliary, — whether they were counted, 

 for instance, in the category of the bones or of the burrows of rodents. With 

 their real nature, of course, we have nothing to do, the question being simply 

 what Thompson meant. 



Now, from the words above quoted, it is clear that he called the soft parts the 

 animal. He states that " Seriolaria are probably the habitations of Polyzose and 

 not Hydrse, though the animals themselves have not been discovered." Therefore 

 it appears that he considered Polyzose. as " the animals," and as a broad name of 

 a group of the Mollusca. 



We, therefore, I think, arrive at the conclusion that Polyzose was given by 

 Thompson as the name for the type of animals which Ehrenberg afterwards 

 grouped among his Bryozoa. 



But the same name Polyzoa appears to have been already employed by Lesson 

 for an Ascidian, and it is asserted that, though in one case it is simply generic, 

 and in the other, as first used, had wider though undefined limits, and though, 

 as Hincks 1 asserts, it never was much used, and has at present lapsed, yet the 

 laws of nomenclature would, at least in spirit, oblige us to regard it as being 

 1 1880, Hincks, ' British Marine Polyzoa,' vol. i, p. cxxxii. 



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