ASTRJRACEA. 
ILYANTHIDAi. 
THE ARROW MUZZLKT. 
Peachia hastata. 
Plate VIII. Fig. 3. 
Specific character. Column lengthened ; conchula bearing from 12 to 20 
lobes, which are mostly bifid ; tentacles marked with arrow-heads. 
Peachia hattata. Go.sse, Linn. Trans, xxi. 207, pi. xxviii. ; Man. Mar. 
Zool. i. 31, fig. 46 ; Ann. N. H. Ser. 3. i. 418. 
GENERAL DESCRIPTION. 
Form. 
Column. Club-, pear-, or spindle-shaped, or cylindrical, the same indi- 
vidual assuming all these forms ; lower extremity rounded, with a minute 
central orifice, distinct, but generally closed, and apparently furnished with 
a sphincter. Surface smooth, but covered with microscopically minute 
suckers, which have the power of strong adhesion to foreign bodies. 
Substance fleshy, becoming more membranous below, where, when in- 
flated, it resembles a blown bladder. 
Disk. Flat, but protrusile, as a low cone ; radii distinct. 
Tentacles. Twelve, in one circle, 
marginal; short, thick, and some- 
what flattened at the foot, tapering 
to a point ; generally carried hori- 
zontally expanded ; sometimes they 
are considerably lengthened and 
attenuated. 
Mouth. Prominent, with a pro- 
trusile cushion-like lip, deeply fur- 
rowed. 
Conchula. There is but one go- 
nidial groove, the edges of which 
are united, the suture marked by 
a depressed line, on each side of 
which the wall is plump. The apical 
edge of the tube rises into a con- 
spicuous organ (conchula), and is cut into papillary lobes, placed in single 
series, but generally so crowded as to overlap each other. Tliey are from 12 
to 20 in number, but are not j>erfectly regular either in form or order. Most 
CONCHULA AND MODTH OF P. HASTATA 
(magnified). 
