246 
these two forms. The flatter specimens keep the same appearance 
as the very young ones in which the marginal part has a rapid 
' growth on account of which long uninterrupted parts of septa develop. 
In the arched specimens the weight of the colony causes a very 
slow growth of the margin and this results in the formation of 
relatively more calicles in the marginal part (fig. 107). 
There is one specimen in the colleotion, which at first sight 
seems to differ from H. robusta in characteristics of specific value. 
The upper surface of this specimen has a very smooth appearance 
(figs. 104 and 116). In the central part the calicles are fairly 
crowded, but in the marginal part there are only few calicles of 
small size. The septa between the calicles in ihe central part have 
assumed a somewhat meandering course. The parts of the septa 
round the calical centres are neatly arranged in a radial manner, 
a columella is in most of the calicles well-developed. The septa 
are thinner than usually in specimens of H. robusta and their 
dentations are of smaller size. The spines on the lower surface 
are arranged in definite rows, they are very small but clearly 
granulated. 
Another specimen in the collection (fig. 115) has somewhat 
thicker septa and larger septal dentations, but agrees in other 
respects closely with the specimen of fig. 116. Between these two 
aberrant specimens and normal specimens of H. robusta every 
intermediate stage is found in specimens of my collection and I 
am therefore convinced that they undoubtedly belong to the same 
species, of which they perhaps may constitute a variation caused 
by local influences. 
The following table contains the measurements of a number of 
very young specimens from the Banda Islands. In some of these 
already a great number of calicles have developed. 
In the greater part of these young specimens a distinet scar 
of detachment is visible. Besides these I have one stalked specimen 
(fig. 99) the anthocyathus of which has a somewhat irregular shape. 
It has afterwards detached from its stalk, which is in comparison 
with the stalk of young Fungiae very large, its dimensions being 
29X23 mm, its height about 18 mm. This peculiariiy is always 
found in the young stages of this species, whenever the scar is 
visible it has always the same large dimensions (figs. 101, 103). 
