XXX 
IXTRODUCTIOX. 
In 1875 Busk issued his “ Catalogue of the Cyclostomatous 
Polyzoa in the Collection of the British Museum,” which served 
for years afterwards as the standard classification of recent Cyclo- 
stomata. It was in many respects a great improvement on his 
arrangement of 1859, but attached probably undue weight to the 
mode of growth. It included only seventeen genera, and the 
classification of this small fauna was a comparatively easy task. 
His scheme was — 
I. Articulata ... 
II. Inarticulata. 
{a) Erectje 
[b) Adnatoe 
Crisiid® ... Crisia and Cr'mdia. 
Idmoneidae 
Tubu]iporid(n ... 
Diastoporid® . . . 
Discoporellidic . . . 
Frondiporida) ... 
Idmmea, Horuero, Retihonicra, 
and Fwstidopora. 
Alecto and Tubulipora. 
IHastopora and Mesenteripora. 
iJiscoporelln , Tenmjsonia, R(fdio- 
pora, Lomopora, ^niiJJefranceia. 
FascicuUpora and Frondipora. 
In 1880 Hincks published his monograph on “ the British 
Marine Polyzoa,” a fauna, however, with so few Cyclostomata 
that it gave no adequate materials for a satisfactory classification. 
It included four families, of which two contained one genus each, 
and the total number of genera was only nine. He separated the 
articulate and inarticulate members into two groups, for which he 
adopted d’Orbigny’s names of Kadicellata and Incrustata. Hincks’ 
treatment of the specific relations of living and fossil species was 
often unsatisfactory, and the most important contribution he then 
made to the classification of Cyclostomata w'as the separation of 
JSornera from the Idmoneidae, as a new family, the Horneridae. 
In 1881 Hr. Hermann Hamm prepared a generic revision of the 
Maastricht Bryozoa, and his classification, though severely criticized 
by W aters, made several valuable contributions to the nomenclature 
of the group. He divided the Maastricht Cyclostomata into Busk’s 
divisions — the Articulata (the Crisiidae) and the Inarticulata ; the 
latter he subdivided into three sections. The Tubuliporina com- 
prise five families, the Hiastoporidea, the Tuhuliporidea, and the 
Idmoneidea, each of Busk as emended by von Beuss ; in addition 
Hamm founded two new and useful families, the Spiroclausidea and 
the Osculiporidea. His second section, the Cerioporina, comprised 
two families, the Cerioporidea and the Badioporidea ; and his third 
section, the Stigmatoporina, included some forms with a central 
