300 ARTHUR DENDY. 



at Naples in 1884, and is referred to by him in the paper already 

 cited. 



Professor Marshall at once took steps to secure a complete series of 

 specimens, showing all stages of this regeneration, and on his return 

 placed his specimens in my hands for description. The greater part 

 of my work in connection with the subject has been done in the labora- 

 tory of the Owens College, under the direction of Professor Marshall, 

 to whom my best thanks are due. Unfortunately the series of speci- 

 mens- proved incomplete in many important respects, and in the 

 summer of 1885, in the hopes of completing it, I went up to continue 

 my investigations at the Scottish Marine Station for Scientific Re- 

 search, at Millport on the Clyde, being enabled to do so through the 

 kindness of Dr. Murray, Director of the Challenger Commission, to 

 whom I am much indebted for the valuable material which I was able 

 to collect there. 



The following is a short account of the main features in the pro- 

 cesses of evisceration and regeneration as observed in Antedon rosaceus 

 {Comatula mediterranea), a species found very abundantly in the 

 Firth of Clyde. 



Before proceeding, it may be well to say a preliminary word or two 

 with regard to the relations of the visceral mass to the arms and calyx 

 in an uninjured Antedon, although I shall have to deal with this ques- 

 tion more fully later on. The entire body of Antedon may be divided 

 roughly into three main parts, the calyx, the arms, and the visceral 

 mass. Of these parts the calyx appears to be the most important, for 

 when an arm is cast off it can easily be regenerated, 1 and the same is 

 now known to be the case with the visceral mass. But no cases are 

 known of an arm or a visceral mass having been able to grow again 

 into a perfect animal after separation from the calyx. This fact, as 

 suggested by Professor Marshall, 2 is to be connected with the fact that 

 the most important part of the nervous system is located in the calyx. 

 The concave surface of the calyx is lined by a thin layer of connective 

 tissue, on which the visceral mass rests and to which it is very closely 

 attached. The visceral mass when removed from the calyx, is a 

 roundish ball, from a quarter to half an inch in diameter and some- 

 what flattened on the ventral surface. This forms such a complete 



1 Perrier, "Sur l'Anatomie et la Regeneration des bras de la Comatula" Archives de 

 Zoologie expinmentale, Tome II., p. 68. 



2 Loc. cit., p. 22 (reprint). 



