CORONULA. 39- 
This species, though closely allied to C. diadema and easily confounded with it, I have 
no doubt is distinct. I owe to the kindness of the Rev. Mr. Image an examination of the 
original specimen figured by Parkinson; and in Mr. Stutchbury’s collection there is a 
similar and more perfect specimen; both of these resemble C. diadema in general form, 
but have been too much worn to be positively identified. ‘The following description is 
drawn up from some compartments collected by Mr. Searles Wood, belonging certainly to 
three and probably to four individuals, one of which was young; as these specimens agree 
in all essential respects, I feel pretty confident that the characters, by which the present 
species differ from C. diadema, are of specific value. 
Structure of Shell_—The longitudinal ribs on each compartment (7. e. the circumferen- 
tial transverse loops), are convex and prominent, as in C. diadema, but they are crossed by 
more prominent ridges of growth (fig. 8a, 8e) than even in the roughest varieties of that 
species, so that the surface of the shell is more rugged. In the three recent species—viz., 
C. diadema, balenaris, and regine, the surface of the wall all round the cavities oc- 
cupied by the whale’s skin, is striated only by very fine longitudinal lmes; but here, the 
outer portion, or that (fig. 87) formed by the transverse loops, is crossed by transverse 
ridges of growth, like, but less prominent, than those on the external surface of the shell. 
The minute teeth, along the lines of junction between the transverse loops, are here less 
regular, and can hardly be said to exist ; for the two edges are locked together by what may 
be more strictly called minute zig-zag ridges (fig. 8d, 8e), than teeth. ‘The exact number of the 
circumferential plications (fig. 84) in the wall of the shell is variable, in the same manner as 
in the three recent species. In the rostrum which has been figured (84, enlarged twice 
its natural size), there is a peculiarity, probably accidental, which I have seen in no 
other specimen—unamely, that one of the transverse circumferential loops at the end of one 
of the original folds of the wall, has ceased to be added to, and therefore may be seen 
(rather on the right hand of the middle of the figure) to terminate in one of the cavities 
between two adjoining folds. The sutural edges of the compound radii (d, fig. 84) 
are abont as thick as, or rather thicker than, in C. diadema; for in the middle part 
they do not reach to the sheath by about half the thickness of the compartment. In the 
same manner as in C. diadema and regina, each ala here rests, not on the internal surface 
(as in C. dalenaris, and in all other Balanidze) of the radius, but on a special plate (c, fig. 
84, 8c); but in C. barbara, instead of there being a deep chamber, running up to the apex 
of the compartment, between the radius and the special plate, this part is filled up almost 
entirely by solid shell. Although the extent to which this chamber is filled up varies a little, 
and although its depth varies a little in C. diadema, yet there is a marked difference between 
the specimens of this latter species, in which the chamber is most filled up, and those of 
C. barbara, 1 which it is least filled up. The alz are thick, as in C. diadema, and their 
sutural edges have a central ridge, sending off on both sides sinuous crests. The basal 
margins of the alz are not short compared with their upper margins, and therefore the 
whole ala is not wedge-formed (fig. 8c); and in this rather important respect C. darbara 
