165 
AMPLEXUS. 
Gen. Cuar. Shell nearly cylindrical, divided into 
chambers by numerous transverse septa; septa 
embracing each other with their reflexed margins. 
AMPLEXUS coralloides. 
TAB. LXXII. 
Seec. Cuar. Tube irregularly bent, longitudinally 
striated; margins of the septa deeply reflexed 
and regularly plaited. 
SEE 
Tue folds on the margin of the septa correspond in width 
to the longitudinal striz of the tube, and are so deep as to 
form elongated cells opening into the chambers; the lines of 
growth are close and rather unequal in depth. The diameter 
and curvature of the tube are both irregular; the septa are 
a fourth or a fifth part the diameter, distant from each other, 
with the margins reflexed to the next septum. The diameter 
is from half an inch to one inch and an half. 
This extraordinary production, an example of the curious 
structure of organic antediluvian remains, is from the Black 
rock at Limerick. 1 have been favoured with specimens by 
my ingenious friends Mr. Wright of Cork, and Mr. Moore 
of Dublin. They seem a type of a peculiar formation or 
era in that Limestone, which requires some penetrating 
research. Its resemblance to a Coral or Madrepore has 
probably caused it to be less noticed, as looking like ordinary 
specimens of branches of some of that tribe. Upon examin- 
ing it, however, its uncommon structure is developed, and 
we are enabled to add another Genus to the multilocular 
shells. 
