488 



DR F. A. BATHER. 



face and its periproctals. The preceding may be regarded as para types. G216, an 

 imprint of the anal face, is referred here with doubt. 



§ 539. Description of Specimens. — The theca is small, flattened, with subovate 

 outline. Thus, in the holotype the sides in the lower half diverge at an angle of about 

 30°, curve round, and then converge at about 90°. In Gr223 the shoulder-angle is 

 about 99°. The outline is, of course, interrupted by the anal lobe. 





Thecal Height. 



Thecal Width. 



G189 



ca. ir>'7 mm. 



ca. 19'5 mm., from which at least 2*5 mm. should 

 be deducted for crushing. 



G135 



ca. 14 „ 



ca. 12-4 mm. 



G213 



ca. 15'5 ,, 



12 mm. seen, but it was probably more. 



G170 



ca. 16-5 „ 



ca. 14-8 mm. 



G223 



21 „ 



ca. 20 mm. 



G216 



ca. 16-5 ,, 





Thus the height is generally, but not always, slightly greater than the width. 



§ 540. Plate 5 is hexagonal, but asymmetrical, stretching more to the left, though 

 not thinning out so much in that direction as it does in some other of the Girvan forms. 

 Its measurements are : — 





Height. 



Width. 



G189 

 G135 

 G213 



G223 ' 



6 4 mm. 



5 „ 

 ca. 46 ,, 

 ca. 8 



6 mm. 



5-2 „ 

 ca. 4-9 „ 



8-7 „ 



§ 541. The rectal lobe is very clearly marked : first, by its relative length ; secondly, 

 by the sharp downward bending of plate 3 ; thirdly, by the elevation of its margins, 

 formed by plates 3 and 8, to constitute a channel with the vent at its extremity. Thus 

 the faecal stream was expelled relatively further and more forcibly away from the 

 intake than appears to have been the case in any other species, although most of the 

 British forms were well favoured in that respect. Hence the trivial name foriolus 

 ("qui foria facile emittit"). In Gl89 (PI. VI. fig. 80) this lobe descends to below 

 flange 4, and the lobe on the other side only to the bottom of flange 1 ; the same 

 relation appears to have obtained in G223 (PI VI. fig. 81). In G 135 (PI. VI. figs. 

 75, 76) the rectal lobe reaches only to the top of flange 3. In G170, where it is very 

 conspicuous, the relations to the stem are not seen, but actual measurements are : 

 width, ca. 5*4 mm. ; length, ca. 5 "5 mm. ; distance below stem-facet, ca. 4 "5 mm. In 

 G223 it has a width ca. 7 mm; length, ca. 5'5 mm.; distance below stem-facet, 

 ca. 5 mm. In Gl89, width, 6-9 mm.; length, ca. 5 mm.; distance below stem- 

 facet, 3 "6 mm. The length is measured from the level of the top of plate 3 on the 



