ASTRjEACEA. 



ILYANTHIDJi. 



THE ARROW MUZZLET. 



PeacMa 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 hastata. Gosse, Linn. Trans, xxi. 267, 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. They are from 12 

 to 20 in number, but are not perfectly regular either in form or order. Most 



CONCHULA AND MOUTH OF P. HASTATA 



{magnified). 



