394 



DR F. A. BATHER. 



In Gl02 some of the smaller plates radiate from a point (PL IT. fig. 25), and there 

 is a suggestion of the same arrangement in others. 



§ 142. G89 and G266 (PI. II. figs. 21, 22) seem to lie in a rather different position 

 from the majority of the specimens, and in them smaller plates surround six or seven acute- 

 angled triangular plates, which meet by their apices as in a valvular arrangement. The 

 point of convergence is to the adbrachial side of the middle line, towards the observer's 

 right, and lies at some distance from the lower margin of the theca, viz. 6 "4 mm. 

 in G89, and about 8"5 mm. in G266. These two specimens seem further peculiar in 

 the possession of a more definite margin to the theca than is usual in the genus, and 

 in the presence of rounded bosses or knobs on some of the plates (§ 136); one such 

 boss is near the margin on the adbrachial side, at the level of the vent. The position 

 of the brachiole indicates that this is the reverse face. It is possible that these specimens 

 represent a distinct species. 



§ 143. The brachial appendage, whenever retained, as in GSO, Gl02, GllO, Gll5, 

 is on the same side of the theca as the plates in question (PI. II. figs. 10, 11). 



§ 144. From these facts it may be inferred that the anus, closed by a sphincter, was 

 in the adbrachial lobe, very close to its adcolumnal border ; that it was surrounded by 

 small plates, those immediately encircling the vent being elongate and triangular ; that 

 these plates did not form actual valves capable of opening as in so many Cystids, 

 but, though lying side by side when the muscles were relaxed, could be drawn up 

 with the folding of the integument and partially imbricated when the sphincter con- 

 tracted ; and that this looseness of structure led to some imbrication when, in process 

 of fossilisation, the periproctal integument was squeezed to the edge of the lobe. This 

 position of the vent and arrangement of periproctals are paralleled in Pleurocystis 

 (§§ 382, 383). 



§ 145. Stem, measurements in millimetres : — 





Total 



Length 



Length of 

 Proximal 



Width at 

 Proximal 



Width at 

 Broken 



Height of 

 Theca. 





Preserved. 



Region. 



End. 



Distal End. 



G71 



30 



11-7 



7-5 



1-6 



ca. 21 



G91 



78-5 



14-5 



6-7 



11 



ca. 26 



G93 



72 



15 



8-5 



2-4 



35 



G105 



81-5 



16 



7 



1-6 



ca. 30 



G90 



30-5 



16-5 



7-7 



2-3 



ca. 26 



G92 



67 



19 



7-6 



2-4 



ca. 30 



In no specimen is the distal extremity preserved, so that neither its form nor the 

 total length of the stem is known. It is also unfortunate that a considerable length 

 of stem is rarely attached to a complete theca. Of those measured, G91 is probably 

 the most complete, and here the stem is more than three times as long as the theca. 

 In G93, G105 (PI. II. fig. 19), and G92, the stems, though manifestly far from 



