PROCEEDINGS OP SOCIETIES. 269 



is very indistinct." Tliis seems to indicate that the very oblique 

 pencils are not as free from aberration as the central. But I agree 

 with Mr, Tolles that contracting the angular aperture would not 

 improve the definition of the peripheral or extreme field of view. 



The eye-piece I employed was the ordinary Huygenian, furnished 

 with the usual stojj employed to limit the field of view, and which was 

 by no means larger than effective with the English object-glasses. 



I am yours faithfully, 



G. W. EOYSTON-PlGOTT. 



PKOCEEDINGS OF SOCIETIES. 



EoYAL Microscopical Society. 



King's College, May 6, 1874. 



Charles Brooke, Esq., F.E.S., President, in the chair. 



The minutes of the preceding meeting were read and confirmed. 



A list of donations to the Society was read, and the thanks of the 

 meeting were voted to the donors. One slide, a poison fang of British 

 viper, presented to the cabinet of the Society by Mr. Elliott, was 

 exhibited imder a microscoj)e in the room. 



The Secretary read a paper by Dr. Anthony " On the Suctorial 

 Organs of the Blow-fly," the subject being illustrated by several 

 beautifully-executed drawings. The paj)er will be found printed at 

 p. 242. 



The thanks of the meeting were unanimously voted to the author. 



Mr. B. T. Lowne said there were one or two points to which he 

 should like to draw attention. The paper itself was a very interesting 

 one, but it contained one or two applications of terms which he thotight 

 were liable to lead to very serious misconceptions. The first of these 

 was the term proboscis. Now this term had always been applied to 

 the whole structure of the fly's tongue, but Dr. Anthony aj^peared to 

 apj)ly it only to the false tracheal tubes which lay upon the surface 

 of the tongue. All naturalists were, however, agreed in calling 

 the whole organ the proboscis, from its supposed resemblance to 

 the proboscis of an elephant. Next, with regard to the so-called 

 suckers, as Dr. Anthony described them. The term had always been 

 applied to the whole surface of the disk. Mr. Lowne here drew upon- 

 the black-board large diagrams of the proboscis and the suctorial disk, 

 and explained by reference to them the structure and action of the suc- 

 torial lobes. What he had called the false tracheal tubes Dr. Anthony 

 had called the proboscis ; they were, however, strictly speaking, not 

 tubes at all, but were merely channels in the skin which were kept 

 open by means of the chitinous rings which had already been described. 

 The wavy lines seen between the false tracheal rays were really a 

 number of little depressions containing small paj)ill8e, as shown in his 

 work on the subject.* These papillte he had little doubt were tacti, 

 * ' Tlie Anatomv and riiyaiologv of the Llow-flv, pi- 4, fig. 3. 



• ■ ' X 2 



