Zoology.'] NATUEAL HISTORY OF VICTORIA. \_Echinodermata. 



Some specimens are of the rare diameter from tip to tip, 

 of three and a half inches ; and one specimen has only seven 

 rays. On some specimens some of the plates of the row of 

 adambulacral plates bordering the ambulacra seem to have only 

 one spine, instead of the usual two ; this is however abnormal, 

 and two spines to each base is neai'ly constant. 



The specimen figured is from Brighton Beach. 



Explanation of Figures. 



Plate 200. — Fig. 1, average specimen, natural size, viewed from below, showing long- 

 spined, interambulacral mouth plates and single-spined interambulacral plates. Fig. la, same, 

 viewed from above, showing madreporiform tubercle and crescentic spinulose plates. Fig. 16, 

 single-spined, large-based interambulacral plates of lower or oral side, magnified three diameters. 

 Fig. Ic, madreporiform tubercle, magnitied four diameters. Fig. 1(^, portion of underside, 

 magnified two diameters, showing two spines to each ambulacral plate, and the single spine of 

 each interambulacral plate. 



Plate 200, Fia. 3. 



ASTERINA GUNNI (Gray). 



Gunn's Cushion Starfish. 



Description. — Moderately tumid, depressed, with six very slightly projecting- 

 blunt rays and six slightly concave intervening sides; taking from centre of mouth 

 to tip of raj' as 100, from same point to middle ot intervening margin, xVir- Inter- 

 ambulacral plates on greater part of lower or oral side each with two divaricating, 

 short spines ; one or two rows of plates next the ambulacra, each with one single, 

 larger spine; adambulacral plates in some individuals with two, in others with three 

 spines each. Thick crescentiform plates of upper surface each with very numerous, 

 small spinules. Madreporiform tubercle large, subtrigonal. Ten or twelve slender 

 spines on each of the trigonal interambulacral oral plates. Colour: Generally purple 

 above, sometimes with reddish between the rays ; flesh colour below, with purplish 

 along sides of ambulacra and round mouth. Measurements : Diameter of ordinary 

 specimen, from tip to tip of rays, 3 in. 6 lines ; to opposite edges of intervening 

 margin, '2 in. 6 lines. 



References. — Asierias calcar, var. b, Lamarck, Hist. Nat. A.S.V., vol. 2, 

 p. 557; ^ Asterina Gunni, Gray, Ann. and Mag. Nat. Hist., 1840, vol. 6, p. 289. 



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