Professor MacGillivray on the Cirripedia. 301 
the prominence at the base of the first foot, and shorter than its cirri, 
the other smaller, on the side of the body. 
The ovarian tube very slender, longer than the last cirri. 
The colour of the body light brown, dotted with darker ; that of the 
cirri greyish-brown ; the pigment dusky brown. In other respects, the 
structure is the same as in Lepas anatifera. 
The tegmen testaceous, compressed, ovate, with the base very oblique, 
straight or slightly concave, the ventral margin convex, slightly sinuate 
toward the end, the dorsal margin curved in the fifth of a circle to the 
angle of the upper plate, then abrupt. 
The lower lateral plate subtriangular, rather convex, rather thick, 
bluish-white, faintly iridescent, highly glossed, concentrically obsoletely 
rugose, with distinct small diverging strie ; the basal margin straight or 
slightly concave, with a small reflexed rim, the umbonal angle not pro- 
jecting, the ventral margin gently convex, the dorsal convex, about half 
the length of the basal, the sutural margin straight ; the apex truncate 
or rectangular. 
The upper lateral plate oblongo-tetragonal, nearly flat, or slightly 
convex, bluish-white, concentrically obsoletely rugose, divergently dis- 
tinctly striulate, the ventral margin straight, the dorsal distinctly angu- 
late, the umbonal point being prominent, the space between it and the 
point straight or concave, and about equal in length to the ventral margin, 
the lower angle very narrow and acute. 
The dorsal plate gently curved, linear-oblong, rising into a prominent 
keel, its sides concave or sloping, deeply grooved, the grooves often 
forming slight denticulations on the keel, the apex very narrow, extend- 
ing nearly to the umbonal angle of the upper plates, its base narrowed, 
abruptly incurved at the end, expanded and emarginate. 
The epidermis on the margins of the calcareous plates very narrow, 
bright scarlet, at the base of the lower plates often forming a regular 
series of angular shreds; between the plates, where it is very narrow, 
and at the base of the tegmen dusky. 
The peduncle shorter than the tegmen, dusky or blackish-brown, ru- 
gose, minutely granulate, its internal tube dark grey or brownish. 
It varies considerably ; but in every form or age is easily distinguish- 
able from Lepas anatifera, into which it does not graduate. Generally 
broadly ovate, the tegmen has its basal line oblique in various degrees, 
sometimes straight, often more or less concave, never convex ; the ven- 
tral line convex to the end of the large plate, then straight or convex ; 
the dorsal line gently convex; the apex sometimes obtuse, generally 
rectangular, sometimes extended, acute or obtuse. The lower plate has 
always a prominent ridge from the umbo to the apex, and is more or 
less convex below. In the upper plate the umbonal angle may be 
more or less prominent, and the margin beyond is straight, concave, or 
rarely convex. The dorsal plate, always sulcate and carinate, may have 
the keel continuous, but generally undulate or denticulate. One or 
more series of depressed dots sometimes extend from the umbo to the 
suture-margin of the lower plate. The stris are sometimes strongly 
marked, generally moderate, sometimes faintly, always more distinctly 
than in Lepas anatifera. 
The bluish tint of the plates is entirely owing to the pigment and 
mantle, for when they are removed the colour is pure white, with a slight 
tinge of lilac-purple. 
‘his species differs from Lepas anatifera in having the tegmen smaller, 
more convex, more oblique at the base, and more distinctly striated. 
The plates are thicker, the lower more convex, with a much more pro- 
minent angular ridge ; the upper more pointed at its lower end, the 
