1897.] Proceedings of Irish Societies, 167 



usually large, in proportion to the total surface ; and the tubercles 

 (called in trade the " pearl ") though of various sizes, are arranged so as 

 to present a pretty regular pattern, the lesser filling up the interstices 

 of the greater. Their vertical axis, also, is usually ata right angle to 

 the long axis of the fish ; which is important to the sword-cutler ; as the 

 hilt covered with such Shagreen gives a good " cut-and-thrust grip." 

 The Japanese, the best artists in Shagreen usually arrange the two or 

 three large spinal tubercles of this fish so as still further to improve the 

 grip. Urogymnus asperrimus furnishes a skin used for some fancy articles. 

 It is a good-sized ray, of all the warm seas of Asia, having many large 

 tubercles produced into sharp curved spines. It is very good for shields. 

 In the East, the Shagreen of rays is more valued than that of the allied 

 saw-fishes, and of sharks and dog-fish ; but there is hardly any cartila- 

 ginous fish that does not furnish some here and there. The Plectognathi, 

 especially Triacanthus and Balistes, furnish a little, of small size and poor 

 quality. 



All bright coloured Shagreens are dyed, and the white seems to be 

 bleached, in the best Japanese specimens. That of English sword-hilts 

 is blackened when the sword is finished. 



Rays, amongst other merits, are much easier to skin than Sharks and 

 Dog-fish ; and, on the Indian coast, men who never fail to skin Trygon 

 sephen can hardly be persuaded to do so with any other fish, unless it 

 comes handy just when they want some Shagreen. 



The exhibitor would be very glad to hear of any analysis of the " pearl '• 

 of true Shagreen. He presumes that the artificial Shagreen is not the 

 subject of any special research at present. 



The second specimen was identified by Mr. G. A. Boulenger, F.R.S., 

 as from Centrophorus granulosus, a deep-sea dog-fish, widely distributed 

 and especially abundant about Madeira. This is used for the hilts of the 

 best English regulation swords. The comparison of this skin with that 

 of our common species of dog-fish would probably be of some interest 

 to amateurs. It is clearly no novelty amongst professional naturalists. 



Dublin Naturai^ists' Fiei^d CIvUB. 



Aprii, 24. — The first Excursion of the season was held, the locality 

 visited being the Sugarloaf Mountain and Calary Bog. A large party 

 took car to the foot of the Sugarloaf and there divided into two sec- 

 tions. One section ascended the Sugarloaf under the guidance of 

 Prof. Cole (the President), who supplied each member of the party with 

 a sketch section of the Leinster Chain, and explained that the Bray and 

 Howth Series (of C'.mbrian or pre-Cambrian age) was composed of shales 

 and sandstones, which were uptilted and hardened, the sandstones 

 being cemented by silica to form quartzites. The Ordovician shales 



