Echinoderms from Port Phillip. 403 



Notes and Descriptions. 

 Antedon Wilsoni. 



General formula Aj^. 



This belongs to the Basicurva-gxou\^ of Dr. Herbert Car- 

 penter *, ancHs the first of the group which I have as yet had 

 the opportunity of examining ; it goes in the second division, 

 or that in which the pinnule-ambulacra are not plated, and 

 has the same general formula as the two species in the ' Chal- 

 lenger' collection. From A. denticulata it may be distin- 

 guished at once not only by the abundance of sacculi but by 

 the first pinnule being the longest ; with A. pusilla it has 

 many more points of resemblance. The first radials are evi- 

 dent and the numbers of the cirri and cirrus-joints are much 

 the same ; but the form of the joints is different ; syzygies 

 are much more numerous, the radials have no tubercles, and 

 the basal joints of the later pinnules have not the same form. 



Centrodorsal slightly convex, with marginal cirri, in two 

 rows, about fifteen in number ; cirrus-joints about thirty, 

 outer cirri longer than inner, owing chiefly to the greater 

 length of the basal joints ; the basal joints are much longer 

 than broad ; this character gradually diminishes in the more 

 distal joints ; the outer cirri are also stouter than the inner. _ 



First radial just visible, the second broader than long, with 

 straight edges but no tubercle, the third radial with a nearly 

 straight proximal edge and two distal axillary curves. 



Ten arms ; a notch between second and third brachial, the 

 succeeding joints overlap a little from side to side; syzygies 

 in the third, sixth, and ninth brachials, then generally in 

 every second. 



Pinnules short, the first is the longest, has ten (or more) 

 joints, the third and fourth of which are very elongated, but 

 it is not at all stout ; the later pinnules are not unlike those 

 oi A. pusilla, as figured by Dr. H. Carpenter. 



Pinnule- ambulacra not plated ; sacculi numerous. 



Colour in spirit white. 



Spread about 60 millim., but none of the arms are quite 

 complete. 



Hah. Port Phillip. 



It is quite clear that this is the representative on the south 

 coast of Australia of A. pusilla of Torres Straits ; it is not 

 often that one gets such obvious signs of relationship. 



* Chall. Reports, part Ix. p. 102. 



