[ 496 ] 



XXXIV. 



EEPOETS ON THE ZOOLOGICAL COLLECTIONS MADE IN 

 TOEEES STEAITS BY PEOFESSOE A. C. HADDON, 



1888-1889. 



NOTES ON A SMALL COLLECTION OF HYDEOCOEALLIN^. 

 By SYDNEY J. HICKSON, M.A., D.Sc, Fellow and Lecturer 

 of Downing College, Cambridge. (Plates XVIIL, XIX., XX.) 



[Kead January 20, 1892.] 



The collection consisted of some pieces of MiUepora Murrayi^. 

 both dried and preserved in spirits, some dried and spirit speci- 

 mens of Distichopora violacea, and a small piece of Stylaster gracilis 

 preserved in spirit. 



In all cases it is difficult to determine satisfactorily specific 

 differences in Hydrocorallines ; but the difficulty is considerably 

 increased when there are only small pieces of the coralla at the 

 disposal of the naturalist, for the general form, colour, and mode 

 of branching of the entire colony have always been taken as some 

 of the most important specific characters of these corals, and these 

 features cannot be determined by the examination of small pieces. 

 Whether these characters are satisfactory is another matter. The 

 fact remains that in order to say with any degree of certainty 

 whether a specimen under examination does or does not belong to 

 species already described by Milne-Edwards, Saville Kent, Yerrill 

 or Moseley, it is necessary to note in the first place the form, 

 colour and mode of branching. As I shall point out later, it is 

 probable that in some cases the male, female, and immature colonies 

 of one and the same species have been raised to the position of 

 separate species by some naturalists, and the tendency of those 

 who in the future examine the structure of both the hard and soft 

 parts together will be rather to diminish than increase the number 

 of existing species. 



The importance of a thorough examination of the soft parts, 

 particularly the male and female organs of reproduction, cannot be 

 too strongly insisted upon, and the thanks of all zoologists are due 



