126 Transaction.?. 



(3) in the Signal Hill plionolite, where neplieline is rare and feldspar of 

 various tvpes abundant, silica is nearly the same as in the nephelinitoid 

 type, alumina is low, and alkalies are also low\ 



EXPLANATION OF PLATES VIII-XL 

 Plate VIII. 

 Geological map of Signal Hill, with sections along lines AA, BB, CC, on map. 



Plate IX. 

 Fig. 1. Map showing locality. 

 Fig. 2. Graphic representation of the chemical composition of the rocks (after Iddings). 



Plate X. 

 Fig. 1. Logan's Point phonolite ; x 200. Shows association of cossyrite and aegirine- 



aiigite. 

 Fig. 2. Signal Hill trachytoid phonolite ; x 45. Crossed nicols. Shows large crystal 



of anorthoclase. 

 Fig. 3. Signal Hill trachytoid phonolite ; x 45. Shows a large crystal of amphibole 



partly resorbed. 

 Fig. 4. Nephelinitoid phonolite ; x 45. Shows the groundmass consisting chielly of 



nepheline with mossy aegirine. 



Plate XI. 

 Fig. a. Logan"s Point phonolite overlying basalt No. 5 on Main North Road, near 



Normanby. 

 Fig. b. Dyke of basalt No. 3, intruded in basalt No. L 



Art. XXII. — Further Notes on New Zealand Starfishes. 

 By H. Farquhar. 

 Communicated by H. B. Kirk, Professor of Biology, Victoria College. 

 [Bead before the Wellington Philosophical Society, ItJi October. 1908.] 



Stegnaster inflatus, Hutton. Plate XII. 



This species has not been figured before : the figure now given is from 

 an example found at Island Bay by Mr. Stuckey, headmaster of the Island 

 Bay State School, and photographed by Mr. A. Hamilton, in which 

 R = 63 mm., and r = 52 mm. 



The species is interesting as being the type of Sladen's genus Stegnaster. 

 In his monograph Sladen says, " I have also added in the following list 

 another genus, Stegnaster (n. gen.), which seems to me necessary. The type 

 of Stegnaster is the starfish described by Hutton under the name Pteraster 

 inflatus, and subsequently placed under Palmipes by Perrier. I consider 

 that the disposition of the papuhe, the membraneous investment of the 

 abactinal area (with the absence of the characteristic tufts of spines and 

 the presence of granules), and the simple character of the armature- of the 

 adambulacral plates, are sufficient to warrant the generic separation of this 

 form from Pahnipes. I also refer to the same genus Asterina ivessli, though 

 not without some hesitation, as the examples I have seen of that species 

 appear to be immature forms."* 



* " Challenger " Reports, vol. xxx, p. 375. 



