CLASSIFICATION OF ACTINIARIA 543 
§Q. Summation of Characters. 
In case it should be felt that the foregoing sections are too 
much of an outline and have too much connexion with evolu- 
tionary speculation, it seems advisable to point out that the 
conclusions have the backing of the sum-of-the-characters 
principle. ‘The following lists will show that the groups sug- 
gested have a solid number of characters binding them together. 
Only main features are included. In connexion with some of 
the details given under the larger groups, T'ext-fig. 16 will be 
found useful. I will take families first, then larger groups. 
FAMILIES. 
GONACTINIDAE. Genera: Gonactinia, Protanthea. 
Common characters, 11. 
1. Definite base. 2. No basilar muscles. 3. Ectodermal muscle 
in body-wall and actinopharynx. 4. Spirocysts in ectoderm of body- 
wall (and actinopharynx ?). 5. No developed sphincter. 6. Tenta- 
cular longitudinal muscle ectodermal. 7. No true siphonoglyphes. 
8. Only the eight protocnemes perfect. 9. Mesenterial musculature 
weak, not forming true retractors. 10. Filaments without ciliated 
tracts. 11. No acontia. 
PrycHODACTIDAE. Genera: Ptychodactis, Dactylan- 
thus. Common characters, 12. 
1. Definite base. 2. No basilar muscles. 3. Ectodermal muscle 
in body-wall and actinopharynx. 4. Spirocysts in ectoderm of 
body-wall (and actinopharynx ?). 5. No developed sphincter. 
6. Tentacular longitudinal muscle ectodermal. 7. At least six, 
usually twelve or more, pairs of perfect mesenteries. 8. Weak 
mesenterial musculature, hardly forming retractors. 9. Filaments 
with no ciliated tracts. 10, Filaments of imperfect mesenteries with 
curious half-funnels at upper termination. 11. Mesenteries with the 
free edge (or its analogue) occupied by filament above, gonad below, 
if present. 12. No acontia. 
CORALLIMORPHIDAE. Genera: Corallimorphus, Cory- 
nactis, Isocorallion. Common characters, 16. 
1. No horny or limy skeleton. 2. Definite base. 3. No basilar 
muscles. 4, Ectodermal muscle in body-wall, at least sometimes, 
perhaps always. 5. Large sting-cells typically present in some part 
002 
