332 SIR SIDNEY F. HAEMKR ON 
On isolating the rows of zooecia, after boiling in Euu de Javelle, the 
method by which the zooecia of the median rows become partially separated 
from the basal surface becomes apparent. As shown by PI. 19. fig. 51, 
the basal wall is very sinuous, the vertical diameter of the body-cavity 
being greatest on the distal side of the length of the zooecium, and smallest 
at the proximal end. The prominent part of the wall reaches the basal 
surface of the branch, while the indented proximal part is excluded from it, 
the lateral walls of the adjacent zooecia sending lobes across this j)art, nearly 
or quite meeting one another. The lozenges formed by the median zooecia 
on the basal wall are thus produced ; and the arrangement will be more 
easil}' understood hj referring to PI. 17. fig. 27 (A. rudis), in which the 
complete lateral outline of the distal median zooecium is represented. It will 
be seen that the greatest prominence of the basal wall corresponds with the 
widest part of the zooecium, while the proximal region of the zooecium is 
narrower, and is either completely excluded from the basal wall or only meets 
it in a linear median region. I believe this to be the method universally 
adopted in this group of species, when the zooecia meet the basal wall 
partially. 
2. Amastigia eudis (Busk). (PI. 17. figs. 26, 27 ; PI. 19. figs. 49, 52.) 
Caberea rudis, Busk, 18521 p. 377 . 1852 % p. 38, pi. 46. figs. 1-3. 
„ „ MacGillivray, 1887, Prodr. Vict., Dec. xiv. p. 137, pi. 136. figs. 1-1 b. 
Menipea marginata, Hincks, 1884, A.M. N. H. (5) xiv. p. 276, pi. 9. figs. 1-1 d ; 
1893, Ibid. (6) xii. p. 143. 
Branches 2-8-serial, coarser than in the preceding species, the zooecia 
larger in all their measurements. Frontal surface strongly convex, the 
marginal zooecia facing outwards. Basal surface flat or concave, the 
marginal zooecia often projecting strongly as a broad, convex, longitudinal 
band on each side, the region of the median rows depressed and concave. 
Marginal zooecium forming a disproportionate part of the basal surface, the 
others reaching the wall in regularly alternating lozenge-like areas, the 
proximal end of each of these zocecia being overlapped by the broad parts of 
thosS of contiguous rows, and excluded from the basal wall or meeting it in 
a linear region. Opesia longer than in A. nuda, the cryptocyst not quite so 
much developed. Spines more uniform in size than in A. nuda, those of the 
marginal zooecia 4, 1, the fourth external more nearly vertical than the 
others. Spines in the other zooecia 2, 2 ; the second of one side in the form 
of a scutum, which does not fill the opesia, its distal lobe pointed (PI. 19. 
fig. 49), its cavity as in A. nuda. Frontal avicularia paired on some of 
the median rows, meeting in a median suture, their rostra directed as in 
the preceding species ; those in r,elation with an ovicell distant from one 
another. Outer frontal avicularium suppressed on the marginal and often 
on the submarginal rows, where the inner avicularium is often enlarged. 
On the marginal zooecia the single frontal avicularium is commonly 
