Newell. — On the Anatomy of the Limpet. 157 



This Decapod is not similar to any which I have previ- 

 ously met with, or of which I have seen descriptions ; it 

 differs chiefly in the shape of the caudal fin, in the large size of 

 two of the sessile arms, in the arrangement of the suckers on 

 the clubs, and in the unusual size of the beak, which, with the 

 tongue, etc., is forwarded with the club. As it is probably a 

 new species, provisionally I venture to dedicate it to Mr. T. 

 W. Kirk, who has done so much good work in describing our 

 Cephalopods. 



The following measurements were taken : — 



Ft. in. 

 Body, from anterior margin of mantle to 



end of tail ... ... ... ... 8 3 



Head, from margin of mantle to base of 

 arms ... «.. ... ..» .. 



Sessile arms 

 Tentacular arms ... 

 Extreme length 



It is to be regretted that a swiftly incoming tide prevented 

 me from obtaining the greatest circumference, which must have 

 been about 8 feet, or the number of suckers on the sessile arms, 

 which I estimate at over 50. 



Aet. XVIII. — On the Anatomy of the Limpet (Patinella 



radians, Quoy). 



By J. A. Newell, B.A. 

 [Read before the Philosophical Institute of Canterbury, 1th October, 1886.] 



Plate XI. 



The following paper is an attempt to compare the structure of 

 the New Zealand Limpet {Patinella radians) with that of the 

 European Patella vulgata, L., as described in Cuvier's 

 *' Memoires," page 15. 



Patinella was made a genus by Professor Dall. The genus 

 was founded upon Patinella magellanica (Gmelin), but that 

 definition has been slightly extended, and made to include all 

 the Patellas of New Zealand.* 



It will be seen that the most important differences (as they 

 will be shown in their proper places,) between Patinella radians 

 and Patella vulgata are — 



1. That in Patinella radians the branchiae do not extend 

 all the way round the head, as they do in Patella vulgata, but 



* 1 



'Proceedings of the Linnean Society of New South Wales, 1884," p. 374. 



