210 EF. R. Cowper Reed— Haverfordwest Fossils. 
The other specimen (Pl. VI, Figs. 9, 9a) has a much less regular 
shape and appears to consist of three segments, all of which may be 
regarded as modified leaves. The lowest and largest one has an 
irregular elongated rhomboidal shape, angulated laterally near the 
base, as in the last described specimen, but not provided with spines ; 
its base is somewhat produced, and its apex is broadly fused with 
a small lanceolate leaf of the usual type. The point of the latter is 
attached to the apex of an equilaterally triangular segment, provided 
at the extremities of its base with short stout grooved straight spines 
directed forwards, like horns. The whole series of three segments 
has the usual epitheca and continuous median ridge on one face, and 
on the other the customary arrangement of cells, which are even 
similarly developed on the peculiar horned triangular segment. 
Length of whole series to tip of spines, 15:°0mm.; length of lowest 
segment, 7°5 mm. ; width of ditto, 4:25 mm. ; length of second segment, 
3:25 mm.; leneth of triangular segment (without spines), 8:25 mm. 
Affinities —The structure of this peculiar Bryozoan reminds us in 
some respects of Ptrlodictya, especially in the arrangement of the 
zocecia, but it is unilaminar instead of bifoliate, and we are not 
sufficiently acquainted with the minute structure of the celluliferous 
surface or with the internal characters to press this comparison. The 
unilaminar and segmented nature of the zoarium, the peculiar 
epitheca, and the occasional presence of spinose processes, with a 
prevailing bilateral symmetry in all parts, prove that this Slade 
Bryozoan belongs to a new and distinct genus to which the name 
Sladina may be suitably appled. The chain of lanceolate segments 
of graduated sizes with the smallest segment at the top suggest 
apical growth of the zoarium. The multiplication of segments may 
take place by transverse constriction, if this is the correct interpre- 
tation of specimen II and similar ones. Whether the apical segments 
are naturally detached to form new zoaria or whether their occasional 
isolated occurrence is accidental must remain an open question for 
the present. 
Definition of genus. — Zoarium unilaminar, composed of flattened 
lanceolate segments, attached in a straight line, with occasionally the 
apical one triangular and furnished with spines; the basal one also 
may be provided with a pair of lateral spines. Each segment is 
bilaterally symmetrical and is covered on one face by a thin medianly 
ridged epitheca with growth-lines concentric to lateral margins. 
Celluliferous face closely set with zocecia, arranged in 2-38 median 
rows (which are generally continuous through the whole chain of 
segments), with irregularly radiating rows of similar cells on each 
side, diverging in a fan-like manner to the lateral margins of each leaf. 
Type, Sladina cateniformis, Slade Beds, Upper Slade, Haverfordwest. 
EXPLANATION OF PLATE VI. 
New Fossits rrom HAvERFORDWEST. 
Fic. 1.  Sladina cateniformis, gen. et sp. nov. Reverse face. x 4. 
,, la. Ditto. Same specimen. Celluliferous face. x 5. 
2. Ditto. Reverse face, showing three segments. x 4. 
,, 3. Ditto. Reverse face, showing small basal segment. x 4. 
4. Ditto. Reverse face, with lowest segment showing transverse constriction. 
x 3 : 
