Happon—The Actiniaria of Torres Straits. 415 
of various cycles reach the cesophagus, and that, too, for the whole or fora variable 
portion of its length; thus there are mesenteries which are truly perfect, others 
which are partially so, while the remainder are imperfect. The directive mesen- 
teries appear also to be very variable in number and position. Occasionally only 
one directive mesentery of a pair may be recognisable, as in a specimen of 
A, Dixoniana; Hertwig (1882, p. 87), and the Dixons (1889, p. 318) have also 
noted this. The same separation of two directives by the intercalation of inci- 
pient mesenteries may occur (ex. Actinioides Dixoniana and A. Papuensis), as has 
been described for Bunodes thallia by the brothers Dixon (Proc. R. D.S., 1889, 
IND S:,) Vi. ps ol8): 
It has been hoped that the disposition of the gonads on the mesenteries might 
prove of taxonomic importance. That this has some value, especially in some 
genera and in other families, there can be no doubt, but it as often as not fails in 
definitiveness in this family, and so cannot at present be relied upon, as is shown 
by the following Table, in which I have divided all the species of which we have 
precise information into two groups according to whether their directive mesen- 
teries are fertile or sterile. In both groups are species that have the other mesen- 
teries of the first cycle fertile. 
If it is permissible to theorise, I would suggest that fertility of all the mesen- 
teries is the primitive condition; in some the directives have become sterile; in 
others this has spread to the mesenteries of the first cycle; while in a few forms 
other cycles have also become sterile, Bolocera multiporum representing an extreme 
case of this tendency. 
Fertile directives, . . . Allmesenteries fertile, Antheomorphe elegans, Macrodac- 
tyla aspera ; 
all perfect mesenteries fertile, Antheopsis Koseirensis ; 
12 perfect mesenteries fertile, Actiniordes Spenceri ; 
some perfect mesenteries fertile, Anemonia carnea, 
Actinioides Dixoniana. 
Sterile directives,. . . All other perfect mesenteries fertile, Actinia equina, 
Condylactis passiflora, Bolocera occidua, B. pan- 
nosa, Myonanthus ambiguus ; 
all mesenteries fertile except Ist cycle, Bolocera 
longicornis, B. patens?, Actinioides Papuensis ; 
Ist cycle fertile, Condylactis cruentata ; 
cf Fs : 4th, 5th, and 6th cyclesonly fertile, Bolocera multiporum. 
The diffuse eaaudarial sphincter muscle is a good character ; but even this is 
not uniform in appearance, that is, if the irregular forms are retained within the 
family. A series could be made out commencing with Antheomorphe, passing 
through Anemonia, Actinia, Actinioides, &c., and ending with Myonanthus; but 
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