1 17 
L. FENESTRALIS. Encrusting, calcareous ; cells ur- 
ceolate, slightly immersed, semi-erect, and reticulated ; 
aperture contracted, circular, with a slight tooth on the 
proximal lip. PI. xxii., Gg. 0. 
Sab. On stones at short distances from the shore, not 
Uncommon. 
This rarely exceeds three fourths of an inch in diameter ; 
it is calcareous and encrusting. The cells are urceolate and 
closely arranged in circular rows ; they do not, like most 
other species, lie horizontal to the crust, but the oral per- 
ilous are elevated, or semi-erect. The surface of the cells 
is rough; several calcareous lines run longitudinally their 
"■hole length, and these are crossed nearly at right angles 
by shorter bands, which give the surface a network appearance 
'vith square meshes. This window-like surtace, has the 
Interspaces filled with a transparent membrane, which is 
niore apparent in dried, than in living specimens. The 
a perture is small, contracted, and circular, with an irre- 
gularity on the proximal lip. 
U. RETICULATA. Encrusting, calcareous; cells urceo- 
late, reticulated ; apertures semi-circular. PI. xxii., fig. 9. 
Sab. On stones &c., not uncommon. Polperro, Lan- 
Sa llos bay; Goran, Mr. Peach. 
This species encrusts the surfaces of stones, about low 
"'a ter mark, in patches varying to an inch and half in di- 
meter. The cells are urceolate and nearly horizontal and, 
Ulongb not heaped together, have no constant order of ar- 
rangement. The cells are rough. From the aperture down 
the centre of the cell lines diverge obliquely downwards and 
°ntwards to the sides of the cells ; these are again crossed 
lines in an irregular manner ; lienee tlio surtace lias a 
f «tioulated appearance. The interspaces or depressions 
formed by these lines are translucent. The lines, however, 
ar e not alike in all the cells; but there is always an approach 
fo the above description, which may therefore be taken as 
? type of the whole. The apertures are semi-circular or 
la lt-moon shaped, large, with a raised rim, which is most 
a Pparent in dried specimens. 
This differs from L. feneslralis in several particulars; the 
c fills are larger and more horizontal ; the reticulations ot no 
* e 8ular form, being sometimes square and at others rhom- 
h °'dal. The lines forming the reticulations diverge from a 
j^dian line, instead of running longitudinally as in L. fenes- 
ra lis j in this the aperture is large and semi-circnlar, in the 
°ther contracted and round. 
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