498 



Forty-fifth Report on the State Museum. 



Discinisca their edges are barbed. The function of the setae seems 

 to have been mainly protective, but in Glottidia, where they 



Fig. 106. —Discinisca atlantica; showing barbed 

 setae.— (Davidson.) 



are of considerable length, they are said, by Morse, to be an 

 important aid to locomotion. 



The Pedicle. 

 This is the organ of attachment to extraneous bodies. In 

 Magellania and the articulate brachiopods generally, it is a short, 

 stout cylinder, whose inner extremity terminates in, and is 



attached to the umbonal surface of the 

 pedicle-valve, its outer extremity being- 

 protruded through the delthyrium or the 

 foramen in species or stages of growth, 

 where the latter exists. Under other 

 circumstances it may be protruded 

 between the valves, or may be alto- 

 gether functionless and atrophied at 

 maturity, as is true of the greater part 

 of early fossil species. This organ is 

 a compact, inelastic cylinder of dense 

 muscular tissue. The exposed portion 

 Fi% am.- Pedicle otMageih m iaaus- \ s covered bv a thick corneous sheath, 



traits with capsule laid open, a, «■' 



pedicle; b, muscular mass of same; an( j the inner extremity is received 



c, horny sheath ; e, margin of orifice 



Kfrs^a^^ps^ief^- into a muscular capsule by means of 

 f'tS^WSSa - ^^ wnioh attachment to the pedicle-valve 

 ^SS^SSooabT" 19 0>rftCh!al is effected. Within the corneous 



covering is a mass of muscular tissue. 



50 



