286 MYEIOZOID^E. 



LOCALITIES. Between Guernsey and Herin (A. M. N.) : 

 coast of Antrim, on shell (Hyndman) . 



There is always a swelling below the orifice ; and not 

 unfrequently this is developed into a massive spatulate 

 process, which gives a very grotesque appearance to the 

 cell. There seem to be generally two or three raised 

 points within the front margin, and, I think, a minute 

 central notch. The fissure on the ovicell is narrow and 

 linear, extending to within a short distance of the lower 

 margin. The mouth of the cell is armed with six very 

 tall and slender spines, of which two are visible below the 

 ovicell. A marked characteristic of this species, as of 

 the allied S. fissa, is the very regular disposition of the 

 cells in linear series. Between the two forms there are 

 many points of resemblance and affinity; but the last- 

 named is at once distinguished by the more elongate cell, 

 the deeply-cut sinus on the lower (secondary) margin, and 

 the wedge-shaped fissure in the ovicell. 



Genus HIPPOTHOA, Lamouroux. 



Der. From 'linroQot), one of the Nereids. 



CATENICELLA (part.), Blainville. 

 ? TEREBRIPORA, D'Orbigny*. 

 TUBULIPORA (sp.), Jameson. 

 MOLLIA (part.), Smitt. 



GENERIC CHARACTER. ZOCECIA distant, caudate, con- 

 nected with one another by a slender prolongation of the 

 lower extremity, so as to form linear series ; branches given 

 off from the sides of the cells ; orifice subterminal, sub- 



* The members of this genus burrow in the shells of certain Mollusks ; 

 but structurally they seem to agree with the present group. Our common 

 H. divaricata erodes to some extent the surface to which it is attached ; and 

 the position of its cells, after their removal, is often marked by a rery distinct 

 depression. 



