CLASSIFICATION OF ACTINIARIA 521 
Eloactis and Haloclava ten pairs, all perfect; in 
Harenactis twelve pairs in two cycles, all perfect; in 
Ilyanthus the number of mesenteries varies, but is the same 
as the number of tentacles, and all are perfect—but there are 
some individual peculiarities as well. 
Unless there is to be much multiplication of families the 
above arrangement seems the best. 
TEXT-FIG. 9. 
Transverse section of Eloactis mazeli. The gaps in some of the 
mesenteries are due to mesenterial stomata. Ten pairs of macro- 
enemes and no microcnemes. a, actinopharynx; b, body-wall; 
r, retractor. (After O. M. Rees. See acknowledgement on 
p- 496.) 
There remains the case of Ilyanthus parthenopeus— 
or Andresia parthenopea as it must now be called. 
This form does not seem to fall in well with the usual idea 
of Ilyanthid structure, apart from its form and rounded 
aboral end. It has long tentacles in four regularly-graded 
cycles, and twenty-four pairs of mesenteries in three graded 
cycles. The mesenterial musculature appears to form only a 
weak layer, not rising into a thick (and typically circumscribed) 
