110 ^K. M. Bale: 



Zooecia elongate oval, with about 11-13 small round fenestrae 

 with fissures converging to a minute sub-oral pore. Orifice semi- 

 ^Uiptic, contracted at base, with two lateral teeth. Avicularian pro- 

 cesses long and narrow, at angles of about 45° with the axis, avicu- 

 laria terminal, very minute. Alae very large, not calcified, hyaline, 

 apparently structureless. 



Ooecium galeate, terminal on one of the cells of a geminate pair; 

 orifice transverse, wider than high, below the lip two long, linear, 

 widely divergent fenestrae with three or four small round ones. 



Type in the National Museum Collection. 



This is a remarkable species, which it is impossible to mistake 

 tor any other, owing to the unique character of the alae. The zooecia 

 are oval, more convex behind than in front; at the back they appear 

 somewhat barrel-shaped, in front they are more ventriccse, and in 

 the lower half is a thin lateral extension on each side with a convex 

 outer border, more conspicuous after decalcification. The zooecia at 

 the ends of the side branches are commonly rather narrower than the 

 others, and possess narrower alae. 



The orifice is rather large, semi-elliptic, but with the sides be- 

 coming convergent near the base, and at the points where the con- 

 vergence begins there are two lateral teeth. The lower side of the 

 •orifice is somewhat convex, and below it is a minute pore, connected 

 with the lip by a straight fissure. The operculum is of similar form 

 to the orifice; its rim is slightly thickened, with an enlargement just 

 at the points subtending the lateral teeth. It has no ornamentation 

 except a vertical bar or median thickening which runs from the top 

 of the operculum downwards for about two-fifths of its length, and is 

 continuous with the rim. The back of the zooecium is plain. 



The fenestrae are small, and form an outer series of seven or 

 eight, enclosing a sub-triangular area in which are from two to five 

 others. They are connected by rough-edged fissures with the sub-oral 

 pore. 



The avicularian processes form long narrow arms rising from the 

 shoulders of the zooecia, tapering outwards to about the middle, and 

 then enlarging slightly to the obtuse ends. The avicularium itself is 

 very minute (only about 15 fi from base to apex) ; it is of the usual 

 sub-triangular form, with rounded angles and a thinner median area; 

 the apical tooth generally found in the larger forms is wanting. A 

 similar avicularium is usually sessile in the upper part of the area be- 

 tween the two cells of a geminate pair. 



The alae are wide and form the most striking feature of the 

 species. The lower chambers are outwardly convex, and the superior 

 ones are still more so; on the summit of the geminate zooecia especi- 

 ally they form large inflated bladder-like expansions. At the two 

 outer angles of the avicularian process the alae form little prominent 

 points, and occasionally the superior inflation of a geminate pair 

 tends towards a bilobed condition, and may run out into similar 

 points. The most remarkable feature of the alae is the entire absence 

 of calcification or of any perceptible structure; they are therefore only 

 visible by their outline, and by any lines of shrinkage which may be 



