ECHINODEEMATA. 157 



4. Antedon carpenter!. (Plate X. figs. A, a-c.) 



Centrodorsal a flattened disk ; about 12 marginal cirri, of almost 

 20 short joints, of which, the lowest are almost twice as broad as 

 they are long ; it is not till we reach the penultimate one that we 

 see a distinct spine, though the dorsal surface of most of them is 

 produced into a minute protuberance. 



Pirst radials not visible ; the second do not or do only slightly 

 touch, united to the third by ligament. Ten arms. Pirst brachials 

 touch, they are nearly oblong and more than twice as wide as long j 

 the second are a little wider on their outer than their inner side ; 

 the third with a syzygy ; fourth to sixth oblong, seventh wider on 

 inner than outer side, eighth wider on their outer than inner, and 

 so on alternately ; twelfth and thirteenth serrated at their distal 

 edge ; the fourteenth syzygial. Thence from four to seven joints 

 between each syzygy. 130-180 joints in the arm. 



The second pinnules on the fourth brachial are very stout, with 

 extraordinarily wide joints, which are armed on either side by 

 spinous projections ; the first pinnule is a little longer than the 

 third. 



Colour white, with purple bands or patches, not always developed 

 at the syzygies. The middle line of the arm often white. 



Arm about 40 millim. long, disk 6 miUim. in diameter, cirri less 

 than 9 millim. long. 



This species has some considerable resemblances to A. serripinna, 

 from which, however, the pinnules alone would, as Mr. Carpenter 

 assures me, be sufficient to distinguish it. 



Port Curtis. 



5. Antedon pumila. (Piate X. figs. B, a-b.) 



Centrodorsal rather wide, rounded ; with about 25 cirri, in three 

 rows, very delicate, of about 12 jointjs, which, from the fourth onward, 

 are a good deal longer than broad, hourglass-shaped, but a little wider 

 at their distal than at their proximal ends ; some are also produced 

 into a small spinous ventral process ; no dorsal spine developed till 

 the penultimate, and that is small. 



First radials just visible, second not in contact ; axillaries tri- 

 angular in shape, sloping backwards in the middle line. Ten arms. 

 First brachial longer without than within, the second within than 

 without and projecting backwards in the middle line ; the third 

 a syzygy wider within than without. The succeeding joints 

 may be incised, so as to leave a lozenge-shaped space between 

 every two ; when this disappears, the joints which have projected 

 strongly forwards on either side alternately become more evenly 

 oblong. 



Syzygies 3, 8, 12, 15 ; then a little rarer. 



Pinnules delicate, the second longer than the first, with elongated 

 joints which are a little wider at their distal than at their proximal 

 end and are produced into a minute spine. 



