490 



a lever enclosed in the centre of the limb. In Model 1 a 

 mechanical stage giving movements of 1 in. vertical and 2| in. 

 horizontal is fitted to the microscope. Model 2 is made to take 

 detachable mechanical stage if required. The instruments have 

 the firm's usual model tripod- claw foot, and the three models 

 shown have respectively rack-centring substage, screw-focusing 

 substage, and plain understage-tube. 



Mr. F. J. Perks read a paper communicated by Mr. W. 

 Wesche, F.R.M.S., on "The Structure of the Eye Surface, and 

 the Sexual Differences of the Eyes, in Diptera." 



A number of drawings illustrating some of the points raised 

 *vere exhibited by Mr. Wesche. 



Mr. T. B. Posseter, F.R.M.S., read a note on "Some Work 

 on the genus Hymenolepis, and -the Description of a New 

 Species." After shortly referring to a paper on the family 

 Taenidae he had read before the Club in October last, the speaker 

 reminded members that, given the hooks on the scolex, one 

 could, with the help of Krabbe, define the specific character of 

 a specimen ; but, minus these organs of attachment, Paillett's 

 generic formulae were to the student of but little value. Further, 

 that Wienland's formulae for his genus Hymenolepis based upon 

 the anatomy of the genitalia, were more reliable generically, and, 

 in conjunction with the hooks, were of inestimable value in 

 determining the species. Species of Hymenolepis ('Taenia) anatina 

 — were exhibited and shortly described. This worm attains a 

 length of from 200 to 300 mm. and a breadth of 2 to 3 mm. A 

 young worm of 70 mm. has about 600 segments, while the 

 largest has probably 2,000 segments or proglottides in the 

 strobila. Copulation takes place when the worm has attained 

 a length of about 65 mm. The head has a simple crown of ten 

 hooks, 65 /x to 72 /x in length. 



At the meeting of the Club held on April 2nd, Mr. 

 C. F. Rousselet, Vice-President, in the Chair, the minutes of the 

 meeting held on March 5th were read and confirmed. 



Messrs. F. W. Gordon, T. E. Saxton, and W. E. W. Baker 

 were balloted for and duly elected members of the Club. 



