On the Classification of the British Polyzoa. 
153 
Lamk. The genus Petrascula , Giimb., is not admitted into 
the new system, at least not under that name. 
The omission of Giimbel’s genus Gyroporella is the more 
noticeable as that genus is particularly interesting with respect 
to the Alpine Formation, and was the first form which led to 
the group being referred to the Calcareous Algaj. Stache found 
it in the Dyasic (Permian) strata of the Gailthal massif. 
Giimbcl, in 1871 *, ranked Diplopora , Schafh., among the truly 
vegetable u Nulliporse,” and subsequently, in 1872, among 
those which he referred to animals. M. Munier-Chalmas’s 
Guembelina is possibly identical with this genus. 
The living Corallines inhabit shallow seas; and thus strata 
including Dactyloporidse may also be regarded as shallow- 
water deposits. These fossils are prevalent in the Alpine 
Limestones (Schlern Dolomite, Wetterstein Limestones), thus 
affording a new argument in favour of Baron Richthofen’s 
and Yon Mojsisovics’s theory of Alpine Coral-reefs. The 
groups of Gyroporellce may have long grown in shallow waters 
at remote periods, just as in our days groups of Nulliporce 
thrive within the surf-zone, and branching Calcareous Algee 
within the less exposed shallows of the reefs in the South Sea. 
XVII.— On the Glassification of the British Polyzoa. 
By the Rev. Thomas Hincks, B.A., F.R.S. 
I propose to give in this paper an outline of certain portions 
of the classification adopted in the * 1 Plistory of the British 
Marine Polyzoa,’ which I hope shortly to publish. I shall 
confine myself for the present to the Cheilostomata, and shall 
merely sketch very slightly the general arrangement, adding a 
brief diagnosis of the new genera which I have found it 
necessary to constitute. I must reserve the discussion of 
many interesting points connected with the subject. 
Class POLYZOA, J. Y. Thompson. 
Subclass Holobranchia, E. Ray Lankester. 
Group a. Ectoprocta , Nitsche. 
Order GYMN0L2EMATA, Allman. 
Suborder i. Cheilostomata, Busk. 
Fam. 1. Aeteidse. 
A single genus, Aetea, Lamx. 
* Abhandlung. d. k.-bayer. Akad. der Wiss. math.-phys. Cl. vol. xi. 
See also Ann. & Mag. Nat. Hist. ser. 4, vol. viii. pp. 70, 71. 
