Zoology.-] NATUEAL HISTORY OF VICTORIA. [Echinodermata. 



The beautiful specimens of this fine sea-urchin figured on our 

 plate were presented by Mr. Bracebridge Wilson, who dredged 

 them near Port Phillip Heads. 



The diversity of the primary spines in different parts irregularly 

 in a given specimen or in different specimens is wonderfully great. 

 The general character of moderate depression, with long thorny 

 spines on the edges, shorter conical thorns on the upper side, and 

 blunt oval tubercles on the underside, is found in most of them ; 

 the whorl of thorns round the tip, either radiating obliquely upwards 

 and outwards round a cup-shaped tip, or inclining so little outwards 

 as sometimes to form only a lamellar fringe round the tip. The 

 irregularity in size and shape not being connected definitely with 

 position. The longitudinal rows of tubercles and thorns on each 

 spine are irregular in number and in disposition. The five longi- 

 tudinal irregular lines of blunt granules seen with a lens are not 

 only on the surface between the tubercles and thorns, but encroach 

 upon them a variable distance. The chief variations of these 

 primary spines I have figured on the plate from our specimens. 

 The secondary spines are only finely marked with granular longi- 

 tudinal striae, without thorns or tubercles ; and are nearly uniform, 

 flattened, and truncated at the tip. 



The pedicillariae are in greater abundance than in any other 

 species I have seen. They are, as usual, of two sorts, one short- 

 stemmed, and globular, the other much longer in the stem, and 

 having the three-valved head of an elongate inversely club-shaped 

 figure. They appear in all the depressions at the angles of the 

 plates, both of the ambulacra! and inter-ambulacral series. 



This species is easily distinguished from the Goniocidaris 

 geranioides, which also occurs in our seas, by the greater depression 

 of the test, more thorny and larger primary spines, and by the 

 comparatively very small size of the ovarian openings, which are a 

 considerable distance within the margins, in the midst of a patch of 

 miliary granules, while in G. geranioides they are very large and 

 touching the margin. The idea occurs to me that G. geranioides 

 may be the female and G. tubaria the male of one species, from 

 the many points of resemblance, and the more striking difference 



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