Prof. G. Lindstrom—On the Operculate Corals. 131 
on the under-side of the coral, but in some cylindrical or conical 
forms they appear all round the exterior. Lindstrom finds that they 
originate, without exception, as small projecting spouts from the 
upper margin of the under-side of the coral. Their succeeding 
development varies exceedingly in different genera of corals; thus, in 
Evidophyllum they become hook-like extensions, in Syringopora they 
are connecting tubes between the corallites, in others again they are 
root-like appendages. It is probable that many so-called Aulopore 
are merely the initial stages of Syringopora, in which the connecting 
tubes are adnate, and develope into fresh corallites. In Diphyphyllum 
the tube-extension proceeds from the summit margin of the coral, 
and is developed into a new polyp. In LKhizophyllum attenuatum, 
Lyon, the under-side is furnished with numerous root-like appen- 
dages, which grow into new corals. In Rhizophyllum gotlandicum 
and elongatum the interior wall of the under-side of the calice 
exhibits numerous apertures which connect with the interior of the 
root-like processes, and thus indicate that the fleshy part of the coral 
extended into them. The appendages may be considered as homo- | 
logous to stolons, which, in some instances, develop into buds or 
germs of new forms, but in the majority of cases merely form tubes 
which serve to attach the coral to its underlying supports. 
The septum in the wrder-side of the coral is the first developed, 
and it becomes also the largest in the corallum; it is styled by 
Lindstrom the primary septum. Next after this appears the opposite 
septum, in the wall of the upper side, whilst the septa of the right 
and left walls appear last in order. There are two kinds of dissepi- 
ments in these corals; one restricted to the loculi, or spaces between 
the septa, the other extends over several septa and loculi. 
Lindstrom divides the Anthozoa operculata into two families ; 
1. Calceolides (or Heterotoechide), in which the septa in the interior 
of each opercular valve are unequal in size; the central septum being 
the largest; and 2. Areopomatide (or Homotoechidz), in which the 
septa of the operculum are equal in size. 
In the family of the Calceolide are two divisions; (A) in which 
there is a single opercular valve, which includes the genera Calceola, 
Rhizophyllum and Platyphyllum; and (B) in which there are four 
valves or lids in the operculum, which comprises the single genus 
Goniophyllum. 
In the family of the Arzopomatide are included (1) Argopoma, 
a new genus with an operculum of four triangular valves; (2) Rhy- 
tidophyllum, a new genus with a single valved operculum, which 
covers a calceola-like coral; and (3) An indetermined genus with a 
single semi-elliptical operculum, with wide, closely-arranged septa 
on its interior surface. 
The well-known Calceola sandalina, Lamarck, the only represen- 
tative of the genus, first noticed as a coral by Briickmann, in 1849, 
but by succeeding authors as late as 1861, referred either to the 
Brachiopoda or Lamellibranchiata, is the most familiar example of 
the group of the operculate corals. A detailed description of the 
species was given by Kunth in 1869, who seems, however, accord- 
