LINNEAN SOCIETY OF LOXDON^. 63 



the author was arguing that sets of species included under several 

 different genera, and even distinct families, had the structure 

 which he was describing under the term" Polyzoa" and, therefore, 

 ought to be removed from the groups with which they had 

 previously been associated. For example, after saying that some 

 of the Sertularian Zoophytes would require to be so removed, 

 " as well as such other genera [italics mine] as may hereafter be 

 found similarly circumstanced," he goes on (Mem. 5, p. 92) to 

 say : — " 1 shall merely indicate here in a general way the whole of 

 the Flustraceae, in many of which I have clearly ascertained tlie 

 .animals to be Polyzose." Surely this indicates that he recognised 

 that whole families and genera \\ould find their proper places in his 

 new group ? 



Then again, on page 97, he refers some of the species of 

 *' Sertularia " (which, by the way, from another passage he 

 evidently regards as a "Family"), in which he has found the 

 animals to be Polyzoa, " to one genus " ; but that does not mean one 

 genus " Polyzoa," for, a few lines below, he proposes the name 

 " Yesieularia " for this genus, showing clearly that he did not 

 regard his term "Polyzoa" as a generic title, and that Vesicularia 

 was only one set of species in the larger assemblage Polyzoa 

 which he was creating. Thompson was in the habit of printing a 

 generic name at the foot of each of his plates — such as Nebalia, 

 Noctihica, etc., in previous Parts of his 'Zoological Eesearches,' 

 —and below the plates of this "Polyzoa" memoir we find the 

 name " Vesicularia," as one would expect from the text. It is 

 clear then, on all these grounds, that he did not regard " Polyzoa" 

 as a genus. 



Finally, in the last paragraph of this paper (p. 100) he says : — 

 "Time and more accurate observations will no doubt add many 

 more species to the above genera, etc." That is, genera of which 

 he had demonstrated the Polyzoon structure or nature. It is 

 therefore obvious that he could not and did not regard the whole 

 assemblage of such genera as one genus to which he was applying 

 the term " Polyzoa," as Mr. Stebbing would apparently have us 

 believe. 



In short, I consider that John Vaughan Thompson knew what 

 he was about, and that although in places his language is a little 

 quaint his meaning is clear : that he was the first to recognise the 

 essential points in Polyzoon structure, as seen, for example, in 

 the genus Vesicularia, or in the larger group " Flustracea," and 

 that he described and figured these adequately in December, 18,'30, 

 in a memoir entitled " On Polyzoa," etc. The very title of his 

 memoir shows that he did not [)ut Polyzoa forward as the name 

 of a genus, since it cites PedircUaria and Vesicidaria as the two 

 new genera he is placing in the larger group Polyzoa. Is that 

 clear recognition and demonstration of a group of allied genera 

 collectively named " Polyzoa " invalidated by the fact that Lesson 

 a few months before applied the term Polyzoa to a genus of 

 Tunicata ? 



March lltli, 1911. W. A. IIeUDMAN. 



