204 Mr. W. S. Kent on the Relationship of 



the other; but both are well grown. ^^ Tlie latter observation 

 is not quite correct, and it is calculated to throw some doubt 

 upon the accuracy of Mr. Stone's words, which are, " I was 

 fortunate in discovering a small larva attached to its victim." 

 The size of the parasitic larva is 3 lines, that of the wasp 5^ ; 

 they have been in spirit since 1865, and were partially dried 

 at the time they were immersed, so that the exact relative 

 size cannot be ascertained ; but the present difference between 

 them justifies Mr. Stone in calling the parasitic larva small, 

 I have carefully examined them, and am satisfied of the Rhi- 

 piphorus-lnrvn being attached to the wasp-larva just below 

 the head ; there is no attachment of the rest of its body : I 

 have separated the bodies, and proved it. 



The last paragra])h of the postscript is entirely supposi- 

 tional. Mr. Murray has not shown me any of his specimens : 

 I have seen no jmpse with the cast skin sticking to their tail ; 

 and if I had, I should only have seen the reverse of what Mr. 

 Stone records, who describes the larva of Rhijyijphorus as 

 having its " mouth buried in the body of the wasp-larva just 

 below the head." 



Let it be distinctly understood that I admit that it is possi- 

 ble, but highly improbable^ that Mr. Stone has recorded mis- 

 taken observations. 



From actual observation I know nothing of the subject. I 

 was never so fortunate as to find a nest infested by the para- 

 site ; but for some years I had the enjoyment of a close corre- 

 spondence with Mr. Stone, and I know him to have been a 

 most accurate and careful observer ; and, until actual observa- 

 tion prove his statements to be fallacious, I shall have a firm 

 belief in their truth. 



XXI. — Hdckel on the Relationship of the Sponges to the Corals. 

 By Wm. S. Kent, F.Z.S., F.R.M.S,, of the Geological 

 Department, British Museum. 



Science does and always must acknowledge herself indebted 

 to those who unveil the mysteries of nature by demonstrating 

 to us the singleness of purpose and the uniformity of the laws 

 which have been in operation from " the beginning." In the 

 last two numbers of the ' Annals,' Mr. Dallas favours us with 

 a translation of Ernst Hiickel's article, published in the 

 ' Jenaische Zeitschrift,' " On the Organization of the Sponges, 

 and their Relationship to the Corals." 



Admitting that once, far away back beyond the limits of 

 the Silurian epoch, there in all probability did exist a some- 



