358 Mr. E. B. Poulton on distasteful Insects. 



EXPLANATION OF PLATE XVII. 



Leucandra Walfordi, figs, 1-9. 



Figs. 1-4. Four specimens of the sponge, enlarged to the same scale of 

 ten diameters. 



Fig. 5. A transverse section of a specimen, showing the thickness of the 

 wall and the cloacal cavity. Enlarged ten diameters. 



Fig. 6. A fragment of the inner surface of the sponge-wall, showing the 

 irregular disposition of the spicules and traces of canals. En- 

 larged sixty diameters. 



Fig. 7. Entire and fragmentary three-rayed spicules of the sponge-wall. 

 Enlarged two hundred diameters. 



Fifj. 8. Entire and fragmentary four-rayed spicules. Similarly enlarged. 



Fiy. 9. Entire and fragmentary rod-like and acerate spicules. Enlarged 

 two hundred diameters. 



[The above are from the Marlstone of the INIiddle Lias at 

 King's Sutton, Northamptonshire.] 



Fiy. 10. Detached thi*ee- and four-rayed spicules of Calcisponges from the 

 Upper Clialk of Croydon and Sutton, Surrey. Enlarged two 

 hundred diameters. 



XLVIT. — Mr, A. G. Butler'' s Remarhs upon distasteful 

 Insects. By Edward B. Poulton, M.A., F.R.S. 



My attention has only just been directed to Mr. Butler's 

 paper in the August number of this Journal. My only object 

 in replying to the extraordinary statements and inferences 

 therein contained is the enlightenment of readers who may 

 mistake the expression of Mr. Butler's conviction that his 

 notes occupy an altogether unique position for a comprehensive 

 guide to the literature of the subject. 



]\Ir. Butler tells us that the attention which a paper of his 

 published many years ago " has since received has been inter- 

 esting, as showing how very little has since been done by 

 naturalists either to prove or disprove the truth of the theories 

 based thereon." 



From this remark any reader who was not acquainted with 

 the subject might reasonably suppose (1) that the theories 

 alluded to were thought out by Mr. Butler ; (2) that Mr. But- 

 ler's observations formed the first basis on which the theories 

 rested, and that very little or nothing has been added in the 

 way of proof or disproof since 1869, when Mr. Butler's paper 

 appeared. 



