ESCIIARID^. 295 



'History;' I suspect it may have been founded on the 

 repent condition of Eucratea chelata (see Plate I. fig. 3) . 



The following is the diagnosis : — 



Zocecia ovoid (more pear-shaped than those of H. divari- 

 cata), connected by a short, stout thread, about one third 

 the length of the cell; orifice longitudinally oval, rather 

 large, with thickened rim ; a short distance from the 

 lower lip a small pearly tubercle, larger in one cell than 

 another.] 



Family XIV.— EscharidaB (part.), Smitt. 



Celleporid^ (part.), Johnston. 

 EscHARiD.E (part.), id. : Busk. 

 Membraniporid.e, (part.), Busk. 



ZoAKiUM calcareous, incrusting, or erect and lamellate, 

 or ramose. Zocecia without a membranous area or 

 raised margins : (a) ivith a simple primary aperture, 

 horseshoe-shaped, or semielliptical, or suborbicular ; or 

 (b) with an elevated secondary orifice inclosing an 

 avicularium ; or (c) ivith a primary orifice having a 

 dentate loiver margin and a secondary orifice chan- 

 nelled in front or entire; or (d) with the lower mar- 

 gin elevated into a macro ; in all cases destitute of 

 a true sinus and special pores. 



This may at first sight appear a somewhat miscellaneous 

 assemblage of forms ; and no doubt it is largely distin- 

 guished by negative characters. But on closer examina- 

 tion it will be found that there is a thread of afiinity 

 running through the whole and linking together the 

 different genera, and that the group is marked by com- 

 mon features and tendencies of much significance. It 

 embraces the residue of forms belonging to this section 

 which do not rank under any of the preceding families, 

 and amongst which there docs not seem to be any such 



