304 The Naturalist of Cumbrae. 



Robertson's zeal as a collector, and readiness both 

 to oblige his friends and forward the cause of science, 

 are pleasantly illustrated by an interesting little 

 episode in the autumn of 1875. The well-known 

 naturalist, Albany Hancock, at the time of his death, 

 in 1873, was engaged in collecting materials for a 

 monograph on the tunicata, that group of organisms 

 which have been supposed by evolutionists to lead 

 with the smallest interval from the invertebrates to 

 the back-boned animals, and in some of which the 

 scientific poet Chamisso first noticed the peculiar 

 series of phenomena since described as " alternation of 

 generations." In the course of a long letter to 

 Robertson, dated September 3, 1875, Norman says 



" Last week I spent a couple of days with Sir W. 

 Armstrong at Cragside (a charming place in North- 

 umberland) and met Professor Huxley, with whom, 

 in conjunction with Mr. J. Hancock and Dr. Embleton, 

 there was a council respecting the condition for 

 publication of Alder and Hancock's work on the 

 tunicata. As a descriptive work on the species we 

 think it may be easily got ready for the printer, and 

 Hancock's " Anatomy and Physiology of the simple 

 Ascidians " is very nearly fully written up, but, though 

 he has left a vast mass of anatomical drawings, the 

 very number of them makes a difficulty as to selection, 

 and they are not worked up sufficiently for the 

 engraver. Had he lived, many figures would have 

 been worked up into one admirable illustration, but 

 no one else can attempt to do this. I hope that 

 Huxley may be induced to write an introduction. In 

 order to do this he wishes to dissect a few fresh 



