M. Lacaze-Duthiers on the Sexes of the Alcyonaria. 455 



most frequently of a pale orange. The other species, M. violaceaj 

 has its tissues of the most beautiful violet that can be imagined; 

 its ova are of a softer shade, in which blue predominates ; its 

 testes are scarcely tinged with a slight tint in which blue pre- 

 dominates still more. But in these two species, whilst the secre- 

 tion of the ovaries is always reduced to about ten ova, the testis 

 produces eight packets formed of from six to twelve capsules. 

 It is therefore easy with the lens, or even with the naked eye, 

 to ascertain the sex of these species ; and it is only quite excep- 

 tionally that I have found upon the same zoanthodema the two 

 kinds of genital glands. 



We should only have to repeat the same things with regard 

 to Primnoa verticillaris, Alcyonium digitatum, and A. palmatum. 

 In the two latter species, when we give a broad scalpel-cut into 

 the lobate fleshy mass of which their zoanthodemata consist, we 

 see, if the animals are breeding, thousands of ova or of testicular 

 capsules separating from the long pedicels which bear them, as 

 in all Alcyonaria^ and escaping from the cavities of the polypes. 



Behryce mollis might sometimes seem to form an exception : 

 but it is to be remarked that its zoanthodemata, when they meet, 

 become soldered together and confounded ; so that sometimes it 

 must appear that there is only a single colony of both sexes, 

 when in reality the sexes have been originally distinct, and the 

 appearance of bisexuality is the result of a graft by approach. 



Alcyonium palmatum lives well and for a long time in aquaria ; 

 so that it is easily observed. When it is well expanded and much 

 inflated, it shows, shining through its attenuated walls, the nu- 

 merous globules of the interior of its cavities, which may easily 

 be recognized as ova or testes from the difi'erence in their form 

 and size. 



In Juncella elongata the parenchyma is of a fine sienna-colour; 

 the ova are large, not numerous, and white : it is therefore easy 

 to ascertain the sex in this species without the aid of magnifying- 

 instruments, after having positively determined histologically 

 the nature of the glands. 



Thus in the species of Alcyonaria with a fixed base, living in 

 the Mediterranean, the sexes appear to be always separate ; for 

 the polypes, like the zoanthodemata, only present one kind of 

 genital glands. 



In the PennatulidcB or free Alcyonaria the same thing is pre- 

 sented. In Pennatula grisea, P. rubra, and P. granulosa I have 

 never found the sexes united ; but I must add that I have ex- 

 amined a far smaller number of individuals than in the case of 

 the other Alcyonaria. 



It is hardly possible to investigate the phenomena of repro- - 

 duction in the lower divisions of the animal kingdom without 



31* 



