Bryozoa. 449 



with a more or less developed suboral peristome, while that of the 

 smaller ones is half as broad as high, nearly semicircular, and 

 provided with a more developed peristome, which as a rule also 

 extends along the lateral margins. In very few zooecia the peristome 

 is provided with a short oral rostrum. The semi- elliptical, semi- 

 circular or quadrangularly rounded poriferous area, which in the 

 larger zooecia at the utmost attain the half length of the whole sub- 

 oral area, sometimes only a third part of its length, is more devel- 

 oped in the smaller zooecia, but I have never seen it occupy the 

 whole frontal area. 



The difference in size between the two forms of zooecia is greatest 

 where they are in connection with each other, and thence as a rule 

 the smaller zooecia graduall}^ increase in size and especially in breadth 

 outwards. At the same time the aperture gradually increases in 

 size and especially in height, and we may find in the margin of the 

 colony a larger or smaller number of zooecia the aperture of Avhich 

 is more or less alike to that of the larger ones. As a rule these 

 zooecia are much shorter, but not rarely broader than the latter, but 

 sometimes we may find in a colony 1 — 3 singly placed zooecia of 

 quite the same form and structure as those surrounding the distal 

 part of the ancestrula, and in some cases I have seen that such a 

 zooecium plays the part as ancestrula to a marginal sub-colony. 



NoRDGAARD mentions that in the colonies examined by him the 

 zooecia in the central portion were glistening and transparent, but 

 the peripheral ones gray and intransparent. I have seen the same 

 in a single colony, and the cause hereof is that the central zooecia 

 have lost the polypides. 



St. 66, Stormbugt, 30—40 m. 



St. 72 c, Stormbugt, 15— 20 m. 



Fam. EscharelUdœ. 



Escharella ventricosa Hassall. 

 Discopora coccinea, forma ventricosa Smitt, op. cit. 1867, Bihang, pp. 



26 and 172. 

 Mucronella ventricosa Hincks, op. cit. p. 363, PI. L, figs. 6—8. 



— — Osburn, op. cit. p. 243, PL XXVI, figs. 59, 59 a. 



The aperture which is surrounded by 4, rarely by 5 or 6 oral 

 spines is provided with a fairly broad, but very low median tooth, 

 the margin of which is straight or a little concave. The suboral 

 peristome is provided with a well-developed, triangular, acuminate 

 somewhat flattened mucro and the whole of the calcareous surface 



34'^ 



