REPORT ON THE CRINOIDEA. 179 



The second brachials bear greatly elongated pinnules of thirty or more cylindrical joints. 

 A similar one on the third brachial, sometimes with rather stouter joints. The next pair 

 are considerably shorter and stouter, and bear more or less developed genital glands. The 

 following pinnules all have relatively stout joints, with the basal pair but little modified. 



Disk and ambulacra naked ; sacculi abundant. 



Colour in spirit, — light reddish-brown, the skeleton somewhat whiter. 



Disk 6 mm.; spread probably 17 cm. 



Localities. — Off Marion Island ; 50 to 75 fathoms. Two specimens. 



Station 145, December 27, 1873; off Marion Island; lat. 46° 43' 0" S., long. 

 38° 4' 30" E.; 140 fathoms ; volcanic sand. One specimen. 



Remarks. — This species, which represents Antedon tenella in the Southern Sea, 

 differs from it in the shortness of the later cirrus-joints (PI. XXXII. fig. 3) and in the 

 characters of the lower pinnules. The second pair are relatively large and stout, with 

 more or less developed genital glands, which do not appear in Antedon tenella until the 

 fourth or even the fifth pair. They are especially large and well developed in the two 

 examples from the smaller depth, and the pinnule-joints are proportionately stout 

 (PL XXXII. fig. 2). Another point of difference from Antedon tenella is the greater 

 backward extension of the axillaries, so that the second radials are almost entirely con- 

 cealed in the middle line of the ray, while there is but little modification of the basal 

 joints in the distal pinnules. 



5. Antedon alternata, n. sp. (PL XVIII. figs. 1-3 ; PL XXXII. figs. 5-9). 

 Specific formula — A.—. 



Centro-dorsal more or less hemispherical, bearing some twenty-five to thirty-five cirri 

 of about fifteen smooth joints, most of which are longer than wide. 



First radials just visible ; the second short and somewhat incised by the rhombic 

 axillaries, which are usually wider than long, with incurved distal edges. Ten arms ; the 

 first brachials barely meeting above the sharp angles of the axillaries and somewhat 

 incised by the quadrate second brachials. The next joints square or oblong till the 

 second syzygy, and the following ones elongately quadrate with very oblique ends. 

 Syzygies in the third, eighth, and twelfth brachials, and then at intervals of one oi 

 sometimes two joints, the latter being the more common at first. 



The second brachial has a slender pinnule about 7 mm. long, and consisting of twenty 

 elongated joints ; the third has a similar but shorter one. The next pair are still shorter 

 but have stouter joints, one or both of them having well-developed genital glands, and 

 the following ones gradually increase in length, becoming slender and delicate, with the 

 two basal joints more or less flattened. 



