Fishes of Massachusetts. 303 
length of the body, broken at its posterior extremity 
into interrupted points or spots. 
Length of specimen, nine inches:—length of 
head, nearly three inches: head broader than the 
body; its depth equal to half of its length. Head 
is made up of seven distinct bony plates covered 
with sparse small black points, which form a perfect 
helmet of defence. The whole upper part of head— 
Occiput, space between eyes, and anterior portion 
to snout, composed of one plate—this portion is 
roughened throughout its whole extent by irregular 
corrugations, and terminates posteriorly in two strong 
spines ;—minute spines are seen also above eyes, at 
their upper anterior and posterior angles: this plate 
is anteriorly widely but not deeply truncated. The 
opereulum is a separate plate, of an irregular trian- 
gular form, having two spines at its posterior ex- 
tremity—the lower larger, and pointing directly 
back; the upper pointing upwards: operculum cov- 
ered with striæ, radiating from the anterior portion 
on each side of the spine towards the circumference. 
Opercle separated from preopercle, by a membrane, 
which enables it to be quite moveable : a wide mem- 
brane also borders its whole margin. The preoper- 
culum is rather small and triangular—slighty move- 
able—divided at its lower portion by a horizontal 
serrated bony ridge which terminates in a naked 
spine ;—beneath this ridge, the inferior portion is' 
corrugated and granulated : from base of preopercle, 
radii diverge to its upper portion. Suborbitar bones 
roughened like top of héad: cheek bones covered 
with elevated strie, slightly serrated upon their 
