REPORT ON THE CRINOIDEA. 147 



always much wider than long. Syzygies in the third, eighth, and twelfth brachials, and 

 then at intervals of two or three joints. 



The first pair of pinnules (on second and third brachials) flagellate, about 12 mm. 

 long, and consisting of forty -five short joints, the basal ones of which are broad, flattened, 

 and somewhat carinate. The next pair sometimes nearly equal to and sometimes shorter 

 than the first. The third pair also shorter, with stouter joints, most of which are 

 distinctly longer than wide, and they generally bear fusiform genital glands. The 

 following pinnules more massive, with squarer joints, which become elongated further out, 

 while the two basal ones become flattened and trapezoidal, with their apposed edges 

 incurved. 



Disk and ambulacra naked. Sacculi abundant in some pinnules, but less so in others. 



Colour in spirit, — white, with purplish or brownish patches. 



Disk 1 mm. ; spread about 1 2 cm. 



Locality.— Station 150, Febuary 2, 1874; lat. 52° 4' S., long, 71° 22' E.; 150 

 fathoms ; coarse gravel; bottom temperature, 35°"2 F. Seven mutilated specimens and 

 one very young. 



Remarks. — This is a smaller and more delicate species than Antedon antarctica, which 

 it resembles in the shortness of the arm -joints ; but the arms generally are much smoother, 

 and there are fewer cirrus-joints, while the third pinnule is much less like the second 

 than is the case in that species (PL XXV. figs. 2, 3 ; PI. XXVII. figs. 15, 16). The three 

 lowest joints are by no means so wide as in Antedon antarctica, but more nearly 

 square, while the following joints till quite near the end are very distinctly longer 

 than broad, which is not the case in Antedon antarctica. Even the first two pinnules 

 of Antedon australis have a tendency in this direction, as compared with the much 

 longer ones of Antedon eschrichti and Antedon antarctica (PI. XXIV. figs. 7, 8 ; PI. 

 XXV. figs. 1. 2). 



Like both these last mentioned types and the other Arctic species as^ell {Antedon 

 quadrata, Antedon hystrix, and Antedon prolixa), Antedon australis affords an excellent 

 illustration of the dimorphic mode of development of the cirri. Its full-grown cirri 

 consist of some twenty- five to thirty-five joints, the first half of which, except those 

 just at the base, are considerably longer than wide. As they get shorter their dorsal 

 edges come to project more and more definitely beyond the bases of the succeeding joints, 

 so that the compressed terminal segments are distinctly spinous (PI. XXVII. fig. 20). 

 There are numerous young cirri of this type round the dorsal pole. They consist of 

 twenty joints, all of which, except the two or three short ones at the base, have a 

 forward projecting dorsal edge (PL XXVII. fig. 18). But on the other hand, the margin 

 of the centro-dorsal bears several young cirri of an altogether different type in various 

 stages of development (PL XXVII. figs. 17, 19). One of them has thirty elongated 



