a Oeneral History oftJie Marine Polyzoa. 159 



and quincunciaHy disposed. But, on the other hand, the 

 zooecium agrees with that of the normal form in the form of 

 the orifice, and in having a small, raised, and pointed avicu- 

 larium on each side of it. These appendages, indeed, are 

 placed somewhat higher up than is usual (more so, indeed, 

 than is shown in mj figure) ; but in this species there is so 

 much variability in their position that this cannot be regarded 

 as a character of any importance. The present form must, I 

 think, be ranked as one more modification of the linearis type. 

 I have figured another specimen of this species (Plate IX. 

 fig. 2), which illustrates still further the variability in the 

 position of the avicularia. 



Family Escliaridsei (part), Smitt. 

 Smittia, Hincks. 



Smitfia nitidaj Verrill. 

 (PI. IX. figs. 5, 5 a.) 



Zooecia subquadrangular (very irregular in shape), disposed 

 in linear series, separated by raised lines, slightly convex, 

 areolated round the margin, or simply punctured, the surface 

 very bright and lustrous, of a delicate white colour, covered 

 ■with large polished granules ; orifice suborbicular, somewhat 

 flattened below ; the peristome raised above and (especially) 

 at the sides, where it rises into prominent points, not elevated 

 in front ; on the lower margin three denticles, two lateral and 

 small, and one larger in the centre ; on each side of the orifice 

 (or on one side only) a subspatulate avicularium (narrow at 

 top, and expanding towards the extremity) raised on a small 

 mound ; sometimes replaced by a gigantic curved avicula- 

 rium, stretching down two thirds of the length of the cell. 

 Ocecium rounded, thickly punctured in front, often invested 

 round the base by a thick granular band ; usually an avicu- 

 larium with pointed mandible at the back ; peristome con- 

 tinued as an arch across' the front of the ooecium, 



Loc. North America ( Verrill) ; Africa, on coral {Miss Jelly). 



Drawings of this species were prepared before I was aware 

 that it had been figured by Prof. Verrill from North- American 

 specimens. I have engraved them, as they show a remark- 

 able modification of the avicularium not noticed by Verrill. 



A detailed diagnosis has been added, no description accom- 

 panying his figure. 



ASPIDOSTOMA, n. gen. 



Gen. char. — Zooecia with a calcareous front wall, destitute 

 of raised margins ; orifice arched above, straight below, pro- 



12* 



