Professor Koelliker. 17* 



powers of reproduction possessed by most aquatic 

 animals, are kept in check only by causes which ope- 

 rate from time to time to their wholesale destruction. 

 To quote many of Mr. Robertson's letters on 

 scientific subjects would not be much to the purpose 

 unless they were accompanied by a manual of marine 

 zoology to throw light on the names and the terms 

 that are used in them, but two that he addressed to- 

 Professor Koelliker may be given as characteristic 

 examples. 



"Millport, September 23, 1864. 

 "MY DEAR SIR, 



" The beautiful little amphipod you gave me 

 yesterday along with the fine specimen of Hyperia 

 galba (Montagu), I think, from the appearance in the 

 bottle, is Iphimedia obesa (Rathke). I find it on the 

 fronds of Laminaria saccharina. However, I will 

 examine it with the microscope, and make sure as 

 soon as I go to Glasgow. I will look and see if I 

 have any specimens of the Clymene that you so kindly 

 wish to associate my name with, but I fear that I 

 may not have them ; I think that it is possible that 

 the Synapta, which I enclosed for you yesterday, may 

 be new. I have not had time or opportunity yet to 

 compare it with Synapta tenera. If not a variety of 

 that species, it is none of those that I have seen. I 

 am very sorry that I have been unable to procure for 

 you a living specimen of Chcstophorus* The tide has 

 not been so low since you came as to allow them to 

 be reached,, We leave here to-morrow morning 

 (Saturday) for Glasgow, and will feel great pleasure 



* Chcctopterns was the name intended. 



