110 in l.l.i;i IN v_\ UNITED STATES NATIONAL MUSEUM 



In L921 Dr. Hubert Lyman Clark published an account of the occurrence of this 

 aperies in northern and eastern Australia. 



In 1938 Dr. Clark recorded and gave notes on 45 specimens collected by himself 

 and Mrs, Clark at Darwin and Broome in 1929 and 1932, and on three collected in 

 the Capricorn Islands by Livingstone and Boardnian in 1930. He compared this form 

 in detail with '/. mirrodiscus. 



ZYGOMETRA ANDROMEDA A. H. CUrk 



Zygtmetraandromeda LH. Clark, Rec. Indian Mas., vol. 7, pt. 3, 1912, p. 269 (description; "India"); 

 Reo vi i '• rn Australian Mas , vol. 1, pt. 3, 1914, p. 123 (comparison with Z. elegans); Unstalked 

 orinoids of the Siboga-Exped., l«.»is, p. 59 (in key; range).— Gislen, Kungl. Fysiogr. Sallak. 

 Handl., now » i , vol. 45, No. 11, 1934, p. 27. 



Diagnostic jeatures. — The cirri are XXI, 27-30 (usually 30), and there are 25 

 arms 50-55 mm. long. The distal border of the radials and the proximal and distal 

 borders of the elements of the division series and to a lesser extent of the first two 

 brachials are thickened and everted, this cvcrsion being finely scalloped or tubercu- 

 lated so that the edges of the ossicles appear beaded. 



Description.— The oentrodorsal is tliin discoidal with the bare dorsal pole large, 

 slightly concave and finely granular, 2.5 mm. in diameter. 



The cirri are XXI, 27-30 (usually the latter), 13 to 15 nun. in length. The longest 

 segments are about one-third again as broad as long. Long and sharp dorsal spines 

 are developed from the eighth or ninth segment onward. 



The arms are about 2") in number, 50 to 55 nun. in length. The division series 

 and arms resemble those of Z. comata, but the distal edges of the radials and the 

 proximal and distal edges of the elements of the division series, and to a lesser extent 

 of the first two brachials, are thickened and everted, this eversion being finely scalloped 

 or tuberculated so that the edges of the ossicles appear beaded. The summit of the 

 eversion may be smooth, but it is usually very finely spinous. The flattened lateral 

 borders of the division series and first two brachials are very finely spinous; the dorsal 

 surface is unmodified. The distal border of the first syz.ygial pair bears a row of small 

 rounded obscure tubercles, and there is usually a similar, but less evident, row at the 

 syzygial line. Beyond the fourth brachial the arms are smooth, resembling those of 

 Z. coma tn. 



P, is 9.5 mm. long and is composed of 24 segments. 



Locality.— "India" (probably Ceylon) [A. H. Clark, 1912] (1, I.M ). 



Remarks. — This species is known only from the type specimen in the Indian 

 Museum, which was described in 1912. Except in the modification of the ends of 

 the radials and ossicles of the division series it does not appear to differ in any way 

 from Z. comata (the following species), of which it is probably the ornate western 

 representative. 



ZYGOMETRA COMATA A. H. Clark 



Plate 4, Figures 13, 14; Plate 5, Figures 15-17 



[See also vol. 1, pt. 1, fig. 252 (centrodorsal), p. 253; fig. 333 (cirri), p. 283; ti- tmdorsal), 



p. 359; pt. 2, figs. 27, 28 (centrodorsal and radial pentagon), p. 20; figs. 143, 144 (arm base), 



D. 83: fie. 711 (disk), n. 341V fiir. 77<1 Inmlmlnprnl HnnnuitB. - ! n 3f.fi 1 



p. 83; fig. 711 (disk), p. 34fi; fig. 779 (ambulacra! deposits), p. 366.] 



