CLASSIFICATION OF ACTINIARIA 519 
can, allowing a fair latitude of definition. It is possible to 
gather them into three fairly clear sets, which must be our 
families. It seems impossible to be content with a subdivision 
which has already been suggested, and based on the nature of 
the sphincter only—into Halcampidae, Halcampomorphidae, 
and Ilyanthidae. This, among other things, means that 
Halcampa and Halcampoides go into different families, 
and this seems to be straining things. 
TEXT-FIG. 8. 
Transverse section of Haleampa chrysanthellum, showing 
Six pairs of macrocnemes and six pairs of microcnemes. 4, acti- 
nopharynx; 6, body-wall; m, microcneme;_ r, retractor. 
(After Haddon. See acknowledgement on p. 496.) 
Taking first the genera Halecampa, Halcampoides, 
Pentactinia, and Scytophorus, we can make for 
these a fairly precise definition, and call them Halcampidae. 
They are Athenaria of more or less vermiform shape, with or 
without suckers or papillae or cuticle or incrustation on the 
body. There may be cinclides in the physa. The tentacles 
may be 8-12, 14, 20, or more, and their longitudinal muscula- 
ture is ectodermal. The sphincter is absent, or weak endo- 
dermal, or weak mesogloeal. The mesenteries have as their 
