id 
BRISSOPSIS. 173 
p- 597; Al. Ag. Rev. Ech. (1872) pp. 95 & 354; Mob. § Biitsch. 
JB. Comm. Kiel, ii. & iii. (1875) p. 150; Ludwig, Mitth. zool. Stat. 
Neap. i. (1879) p. 562; Al. Ag. Mem, Mus. C. Z. x. 1. (1883) p. 69; 
Koehler, Ann. Mus. Marseille, i, 3. (1883) p. 185; Carus, Prod. 
Faun. Mediter. (1884) p.103,; Rathbun, Proc. US. Nat. Mus. ix. 
(1886) p. 289; Hoyle, J. Linn. Soc. xx. (1890) p. 458; Scott, Rep. 
Scot. Fishery Board, 1889 (1890), p. 316; ad. Ann. Scot. Nat. Hist. 
1892, p. 50. 
Brissiopsis lyrifera, Gray, Brit. Rad. (1848) p. 7; td. Cat. Ech. 
(1855) p. 55. 
This species may be at once recognized by the lyre- or fiddle- 
shaped black fasciole on the dorsal surface. 
Body elongated or more or less oval, rather higher posteriorly 
than anteriorly; pretty closely covered with rather short and 
delicate, slightly curved spines, which are longest and strongest on 
the edges of the ambulacral petals and just in front of the mouth. 
The general coloration is brown, but the spines are light yellow ; 
the finer spines of the peripetalar and of the subanal fascioles are 
very much darker. 
The peripetalar fasciole varies a good deal in the details of its 
course, but its general direction is as follows: there is a band at 
right angles to the anterior odd ambulacrum, placed at the point 
where the test begins to sheer downwards; on either side it takes a 
more or less angulated course to the tips of the antero-lateral petals ; 
the band then curves inwards, sweeps outwards around the postero- 
lateral petals of either side, and joins its fellow in a nearly straight 
transverse band. The subanal fasciole, which is of a transversely 
elongated oval form, varies somewhat in the extent of its distinct- 
ness ; the spines within it are disposed in two diverging tufts, but 
are not prominent as in Spatangus purpureus. 
The tubercles on the test are rather coarse, and are coarsest 
below and anteriorly, and are nowhere very closely packed. The 
part within the peripetalar fasciole is longer for the antero-lateral 
than for the postero-lateral ambulacra, and the former are also 
somewhat more deeply excavated. The madreporite, which lies 
between the proximal ends of the latter, is rather small and very 
finely punctured. ‘The lower lip is hardly at all curved from side 
to side or from above downwards. The periproct is irregularly oval 
in form and its somewhat longer axis is vertical; the outermost or 
peripheral plates are of some size. When the spines are particularly 
well-developed the peripetalar fasciole is a good deal obscured, the 
spines within the two fascioles become much more prominent, and 
those below much longer than ordinary. 
A great quantity of mud becomes entangled in the spines of this 
species. 
Length. Breadth, Height. Peristome. Periproct. 
62 59°5 29 11:3 < 
53 46 31 10 6 
dL 47-5 33 10 7 
40 36 23 6 4 
34 30°5 21 5 
