198 vine: YORKSHIRE CARBONIFEROUS AND PERMIAN POLYZOA. 
1884. E. 0. Ulrich, Jour. Cincin. Soc. Nat. Hist., vol. vii., p. 26. 
1883-4. G. R. Vine (Additional Notes, p. 105), Proc. Yorksh. Geol. 
Soc, vol. viii. 
Zoarium ramose, branches slender. Zowcia tubular, radiating 
in all directions from an imaginary axis. Zooecial apertures circular 
or oval, placed at the bottom of more or less obviously impressed, 
sloping rhomboidal or hexagonal vestibules. Ridges separating vesti- 
bules spiniferous, spines hollow, and of two kinds, large and small, 
the latter most numerous, and surrounding the vestibules, while 
larger spines are occasionally developed only at the upper extremity 
of the cell. 
Type of Meek R. lepidodendroidea, Up. Coal Measures, Nebraska. 
As species of this genus are rather abundant in American rocks, 
I have adopted, to a large extent, the definitions given by Mr. Ulrich 
in the Journal cited above, 1884. 
I have already quoted the names of several species of Rhomhopora 
as apparent allies of Yorkshire forms. The following is a full and 
unprejudiced description of the Yorkshire species that I have hereto- 
fore detected. 
I. RhOMBOPORA LEPIDODENDROIDEA ? Meek. 
1871. R. lepidodendroidea, Meek. Pakeon. Eastern Nebraska, 
p. 141., pi. vii., fig 2, &c. 
1884. R. lepidodendroidea, Ulrich." Jour. Cincin. Soc. Nat. Hist., 
vol. vii., pp. 26-27, pL i., fig. 1. 
1884. R. lepidodendroidea ? Vine. (Additional Notes) Proc. Yorks. 
Geol. Soc, vol. viii., p. 106. 
The above is the type species of Meek, and when comparing 
American examples with our own, I think I may place its existence 
here on record. The Yorkshire examples are much less slender than 
the American, but there is a close similarity in the facial features : 
but as my material is limited I still retain the doubt. 
Locality : Hurst, North Yorkshire. 
2. Rhombopora similis, PhilL, sp. 
1841. Ceriopora simiHs, Phill. Palaeoz. Fossils of Devon, &c. 
1881. „ Vine, Proc. Yorks. Geol Soc, vol. vn., 
p, 338. 
