412 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
separated from each other and from the margin of the colony. The 
tendency to irregularity and individual variation in the shape of the 
colony is considerable, but nearly all the shapes are readily recognized 
as modifications of the capitate form above described. 
In localities jiarticularly favorable for its growth this species may 
develop into turbinate masses or lobes similar in size and appearance 
to those of the cnnstcUaium form of .1. pcUucidum, and as in that species 
these lobes may be aggregated or even completely fused into a hemi- 
spherical or flattened mass sometimes 80 mm. in diameter attached by 
a more or less narrowed base. 
In spite of the occasional resemblance in external form between this 
species and consfcUatum, there are very evident difterences in the 
character of the test substance and size and details of the zooids. In 
this species, the test is firmer and more transparent, in fresh specimens 
of a pale translucent bluish white color, allowing the zooids to be 
distinctly seen. In alcoholic specimens it loses more or less of this 
transparency, becoming of a yellowish white color or some shade of 
gray ol" brownish gray, and varies in consistency from rather firm to 
decidedly tough and fibrous. The upper part of the colony has usually 
a smooth glabrous surface comparatively or completely free from 
adhering or imbedded sand grains or other foreign bodies. The basal 
parts of the colony are generally firmer and more opaque, and may 
contain much sand and other foreign matter. In some specimens the 
majority of the zooids will be found with their long axis perpendicular 
to the upper surface or parallel to the main axis of the colony; in others 
they lie in all sorts of positions and directions. In life "the branchiae 
are light yellow; the stomach dark orange, ovaries yellowish white, 
the eggs containing embryos bright orange yellow" (^'errill, 1871a, 
p. 289). 
The zooids are small; a length of from 4 to 5 mm. when the 
post-abdomen is shorter than the thorax and abdomen together, or of 
from 7 to 8 mm. when the post-abdomen is long, is usually not exceeded 
in the alcoholic specimens, and in many colonies their average size is 
smaller. Although a large number of specimens was examined, the 
zooids were always found in a violent state of contraction. The 
branchial orifice is six-lobed; the atrial orifice may or may not be 
noticeably lobed, and is provided with a well developed languet, which, 
as noted also by Ritter and Hartmeyer in ^4. transhicidum, often has a 
pair of lateral lappets or processes near its base. In some colonies 
