112 Mr. T. V. Wollaston on Microxylobius Westwoodii. 



under his order of Peritriclious Infusoria *, in which it forms 

 the true ordinal type, the "nucleus and central point" to which 

 the other groups approximate upwards and downwards. 



We have treated the systematic history of the Vorticellan 

 family in more detail perhaps than the following observations 

 may render necessary ; but the history of the classification of a 

 group of animals is always the true expression of the develop- 

 ment of the knowledge of it ; and in the present case it is of 

 the greater interest, because it shows in how rare a fashion the 

 Vorticellina have shown themselves to be a coherent and 

 closed group, as, in spite of all efforts at further development, 

 the systematic combination has remained essentially the same, 

 although the characters in the meanwhile, as we have seen, 

 have attained a much greater sharpness. But, besides this, 

 we shall be able often to make use of the stand-point arrived 

 at in the above explanations in our further statements, in 

 order to attach our own observations, without being constantly 

 obliged to make long digressions. 



[To be continued.] 



XIII. — On the Microxylobius Westwoodii, Chevr., from 

 . St. Helena. By T. Vernon Wollaston, M.A., F.L.S. 



Having lately had an opportunity, through the kindness of 

 W. W. Saunders, Esq., of examining the type of the little 

 Curculionideous MicroxyJolnus Westwoodii, from St. Helena, 

 which was described in the first volume of the Entomological 

 Society's Transactions, and which, after the lapse of thirty-six 

 years, still remains unique in his collection, I have thought 

 that it would be worth Avhile to draw out an accurate diagnosis 

 of it, in order to call attention to the exact characters in which 

 it recedes from the other members of the genus (twelve in 

 number) which have hitherto been brought to light. And 

 this seems to be the more desirable, since the few words of 

 M. Chevrolat which take the place of a description are quite 

 insufficient for even its approximate identification. Judging 

 solely from the excellent figure of it which was supplied by 

 Prof. Westwood, I had imagined that it might perhaps prove 

 to be identical with the species which I enunciated, in 1869, 

 under the name of vestitus ; but I now perceive that it is not 

 only totally distinct from that insect, but equally so (as may 

 be gathered from the subjoined remarks) from every other 

 Microxyhhius which has come under my notice. 



* Der Organismus der Infusionsthiere, ii. p. 168. 



