108 On an Erroneous Echinodermal Identification. 



A specimen labelled by Hutton, denuded of spines, 

 measures 34 mm. in diameter, 22 mm. in height. The 

 interambulacrum, at the ambitus, measures 12 ram., the 

 ambulacrum 8 mm., and the poriferous zone 1*5 mm. 



Button's account of the type in the Colonial Museum, 

 Wellington, will be found in ■■ Catalogue of the Echinoderraata 

 of New Zealand,' 1872, p. 12. As this publication may not 

 be widely accessible 1 quote it : — 



^' Height f of the diameter ; pores forming a rather 

 irregular zigzag row of single pairs ; ambulacral plates with 

 one primary tubercle ; interambulacral with three on the 

 lower half, but near the apex with one central tubercle sur- 

 rounded by smaller ones on the edge of the plate ; ambulacra 

 narrow ; tubercles moderate ; spines tapering, longitudinally 

 grooved; grooves much broader than the ridges. Shell 

 brownish purple ; spines reddish purple, broadly tipped with 

 white. 



" Diameter 1 inch." 



It may be as well to give details of this co-type now before 

 me. Each interambulacral plate at the ambitus bears one 

 primary, of a diameter nearly equal to the height of the 

 plate ; on the mesial side one secondary ; and on the ambu- 

 lacral side two secondaries, of about half the size of the 

 primary : i. e. four tubercles in a row. Every alternate plate 

 bears two horizontal rows of two secondaries on the ambu- 

 lacral side of the primary. 



The tertiaries and miliaries are numerous. Above the 

 ambitus the secondaries decrease in size and lose the linear 

 arrangement, so that near the abactinal ring each plate bears 

 only one primary. 



Each ambulacral plate bears one primar}', rather smaller 

 than that in the interambulacrum and situate about the 

 middle of the plate. On each side a secondary, the mesial 

 being the larger ; above the ambitus that on the side of tlie 

 poriferous zone becomes much smaller, while the other 

 secondary also decreases in size towards abactinal ring, to be 

 replaced ultimately by a miliary. The pores are arranged 

 much as in F. huttoni. 



I have other specimens of larger size than this, the greatest 

 being 50 mm. diameter X 30 mm. high. They all agree 

 in colour of test and spines, though the extent of the white 

 tip varies, and the colour of the base is rather red than reddish 

 purple. 



The general form is that of a depressed spheroid. 



Dunedin, 

 November 6, 1907. 



