NO. 15 RECENT CRINOIDS IN BRITISH MUSEUM CLARK 57 



proportionately shorter and do not taper distally as do those of L. 

 phalangium, so that they appear considerably stouter distally. While 

 in the proximal third of the cirri the segments are of the same pro- 

 portions as those in the proximal third of the cirri of L. phalangium, 

 in the distal half they become shorter so that in the distal third they 

 are usually only one-third again as long as broad and may be even 

 shorter, nearly or quite as broad as long. In L. phalangium there is 

 no decrease in the proportionate length of the cirrus segments dis- 

 tally, all the segments being about twice as long as broad. In L. 

 celticus as the segments become shorter in the outer part of the cirri 

 the distal dorsal edge becomes somewhat swollen so that the dorsal 

 profile of the cirri is slightly scalloped ; in L. phalangium these edges 

 are always perfectly smooth. 



The specimens from the Minch have the cirri XIV-XXIV, 43-50 

 ( usually 43-47) , 30 mm. to 40 mm. (usually 35 mm. to 40 mm.) long ; 

 the arms are from 105 mm. to 115 mm. in length; the distal inter- 

 syzygial interval was counted in twenty-seven cases, and found to be : 

 two oblique muscular articulations,- once ; three oblique muscular 

 articulations, ten times ; four oblique muscular articulations, ten 

 times ; five oblique muscular articulations, five times ; six oblique 

 muscular articulations, once. 



Genus ADELOMETRA A. H. Clark 



ADELOMETRA ANGUSTIRADIA (P. H. Carpenter) 



Antcdon angustiradia 1888. P. H. Carpenter, "Challenger" Report, Co- 

 matulae, p. 253 (1). , 



i. "Challenger" Station No. 192. — One specimen. 



Genus BALANOMETRA A. H. Clark 



BALANOMETRA BALANOIDES (P. H. Carpenter) 



Antedon balanoides 1888. P. H. Carpenter, " Challenger " Report, Comatu- 

 lae, p. 207 ( 1 ) . 



i. "Challenger" Station No. 201. — One specimen. 



Subfamily Perometrtn^e A. H. Clark 

 Genus PEROMETRA A. H. Clark 

 PEROMETRA AFRA A. H. Clark 



Perometra afra 191 1. A. H. Clark, Proc. U. S. Nat. Mus., vol. 40, p. 43 (1). 

 1. Providence Island, northeast of Madagascar; 125 fathoms; 

 Professor J. Stanley Gardiner. — Four specimens, three with four- 

 teen and one with eleven arms. These were described in detail in 

 the reference cited. 



