212 
NOTES AND MEMORANDA. 
In dealing with the classification of the group the author suggests 
considerable modifications upon that of Haeckel. He objects (as un- 
natural) to Haeckel’s division of the group into Monozoa or Monocyttaria 
and Polyzoa or Polycyttaria, the aggregation or non-aggregation of 
zooids into colonies being, in his opinion, a comparatively unim- 
portant distinction, especially as individual zooids of the compound 
species are found also in a single and separate condition, and he 
suggests the union of Haeckel’s fifteen groups into larger aggrega- 
tions, reducing them to seven. These are : — 
Vesiculata. — Formed by separating from Haeckel’s Collida those 
forms (viz. Tlialassicolla, Thalassolampe, AulacantJia, and PJiysematium) 
which have a nuclear vesicle — the presence or absence of which the 
author, following Hertwig, considers as of greater importance as a 
classificatory character than any characters derived from the skeleton — 
and uniting them with his Aulospha^kida and the other genera (Heli- 
osphcera and Diplosplicera, part of his Ethmosph^rida and the new 
form Myxobrachia), which possess that structure. 
CoLLOzoA. — Formed of the remaining Collida (Thalassosplicera 
and Tlialassoplancta) and Haeckel’s Sph^rozoida and Collosph^rida 
(which constitute his Polycyttaria). 
PoLTCYSTiNA. — Formed of Haeckel’s Acanthodesmida and Cyrtida, 
and the rest of his Ethmosph^rida, associated together as being ecto- 
lithic, non-vesiculate, simple forms, the skeleton of which consists of 
more than detached spicula. 
Flagellifera. — Formed of the genera Spongocyclia and Spongo- 
astericus (part of Haeckel’s Spongurid^) and EucMtonia, a genus of his 
Discida — the possession of a large fiagellum being, the author con- 
siders, a very important and natural character. 
Acanthometrida. — Formed by adding to the similarly named 
group of Haeckel those of his Ommatida (Dorataspis and Haliommati- 
dum), whose radii meet together in the centre of the capsule — a very 
special and peculiar condition — and the author regarding as unna- 
tural the separation from Haeckel’s Acanthometrida of these, latter 
forms, which differ only in having tangential outgrowths from their 
radii so disposed as by their mutual junction to form an external 
shell. Haeckel’s Diploconida being also added as a third sub-section 
as presenting the special character of centrally-joined radii, regard- 
ing its conical structure as a mere special modification of radial 
structure. 
Entosph^erida. — Comprising the remainder of Haeckel’s Omma- 
tida and part of his Spongurida [Dictyoplegma, Spongodictywn, Pliizo- 
spJicera and Spongosphcera), the latter being an unnatural group, the 
possession of a spongy skeleton existing in very different forms. 
Adding also his Cladocoocida and Ccelodendrida as forms possessing 
an intracapsular, more or less spheroidal shell — the latter from its 
exceedingly noteworthy mode of growth — by absorption and rede- 
position — possibly being entitled to be made a distinct primary group. 
Disoida. — Comprising the group so named by Haeckel (except 
Eiichitonia) with the rest {Spongodiscida and Stylospongia) of his 
Spongurida and his Lithelida. 
