58 
VINE : NEW nit BUT LITTLE KNOWN EOCENE POLYZOA. 
the surface both the orifices of the true zooecia and the accessory 
cells (" cavites intersquelettiques "). Dr. Pergens in the grouping of 
the Cretacious Polyzoa places this genus in the family Diastoporida?, 
and he remarks (Op. cit., p. 328) that " Dixatia comprises those 
species with ' cavities intersquelettiques ' strongly developed. This 
difference between Ditaxia and Diastopora is however of little 
value, and perhaps some day anatomical researches will compel us 
to unite these genera into one," I cannot agree with this opinion 
in the present case, for after a careful study of the type species 
of Hagenow, Ditaxia anomalopora, there seems to me to be no 
relationship whatever between it and Diastopora as generally under- 
stood. I have no objection to the grouping of the following species 
however under the genus Ditaxia, as adopted by Dr. Pergens in his 
revision of d'Orbigny's labours (Op. cit., p. 337). 
1. Ditaxia anomalopora, Goldf., d'Orb., Terr. Cret., p. 953. 
2. ,, variabilis, d'Orb (*= Semimulticlausa id.) I.e., p. 900. 
3. ,, papularia, Mich. (= Reptomulticlausa id., d'Orb.) I.e., 
p. 901. 
4. „ nodosa, d'Orb. (= Seminodicrescis id.) I.e., p. 1067. 
5. ,, tubulosa, d'Orb. (= Semicrescis id.) I.e., p. 1073. 
6. ,, ramosa, d'Orb. (= Semimulticrescis id.) I.e., 1078. 
3. Ditaxia variabilis, d'Orb. 
1850-52. Semimulticlausa variabilis, d'Orb., Terr. Cret., vol. v., 
p. 900, pi. 767, figs. 5-10. 
1890. Ditaxia variabilis, Perg. Revis. des Bryoz. du Cret., p. 337. 
This species is represented by several examples which closely 
resemble d'Orbigny's figure, but as such a variety of forms are associ- 
ated under the generic term Ditaxia by Dr. Pergens, I forbear 
making any remarks on the genus Ditaxia at present. Certainly 
Semimulticrescis ramosa, d'Orb. (pi. 800, figs. 15-17) in some of its 
features resembles the above, but the Eocene forms, when magnified, 
are more akin to D. variabilis than to D. ramosa. 
Horizons and Localities : London Clay, Fareham ; Cretaceous, 
22nd stage, Villedien, Lavardin (Loir-et-Cher) ; Tours (Indre-et- 
Loire) d'Orb. 
