386 
VINE: NOTES ON FOSSIL POLYZOA. 
Fig- 4, T. Urii^ Young, showing- the incomplete tabulae at 
different stages of growth. 
2. Heterotkypa* delicatula (n. sp.) PL XXL, fig. 1. 
Corallum slender (ramose ?) bearing two kinds of corallites on 
the surface; (a) normal ; cahces circular, but of rather unequal size, 
about five to the half line, separated from each other by a single 
row of (b) intermediary pores. Monticules feebly developed, indi- 
cated by rather larger calices, and occasionally separated from each 
other by at least two rows of intermediary pores. 
Localities : Hurst, North Yorkshire. 
One would almost imagine that these two species should be 
united if we went by the measurement of the superficial calices only. 
Both forms yield the same results — five calices to half line — but one 
consideration with me determines the separation. The calices of 
M. tumida, so far as a superficial examination can afford details, 
come up to the surface with sharp and distinct edge, and it is only 
when slightly rubbed that the separating spinal on intermediary 
opening's are visible — in the present species the whole of the char- 
acters are drawn up from superficial examination. At first I was 
inclined to place the form as a variety of Phillips' Ceriopora inter- 
porosa^ but M'Coy in his diagnoses of Phillips' sp. says " cells oval," 
and in the Scotch specimens which pass by this name, the cells are 
distinctly oval. It is here that the value of Mr. Ulrich's labours on 
the American Palaeozoic Bryozoa is appreciated by me as a corrective 
of my own ; not so much on account of his diagnoses, as on account 
of the careful localization of the various fossils submitted to him for 
examination. In one species which he names and figures as Rhomho- 
pora crassa, Ul.f the fig. pi. 1., f. 2, the normal cell openings with 
thin intermediary pores very closely resemble our own. And of this 
species Mr. Ulrich says (op. cit., p. 26) " Through R. crassa, Ul., 
and Ceriopora interporosa^\ Phill., we can trace a resemblance to 
Carboniferous species of Batosfomella (e.g. B. tumida, Phill.)" There 
is not, however, any resemblance between the present Yorkshire 
* See Nicholson's Genus Monticulipora (Sub Genus Heterotrypa). 
t Jour. Cine. Soc. Nat. Hist., April 1884, p. 28. 
X Judgment founded upon Scotch specimens sent to him by me. 
