204 ME. J. T. CUNTvriNGnAM OK THE [Mar. 15, 



constituting the type of a new genus, which was proposed to be 

 called Eupatldstonia. Of the ISew Zealand species treated of 16 

 were described as new, and the new generic term Tracliylehens 

 was proposed for tlie reception of Cythere seabroctmeata, Brady. 

 This paper will be published in full in the ' Transactions,' 



The following papers were read : — 



1. On tlie Early Post-larval Stages of the Common Crab 

 {Cancer pagurus), and on the Affinity of that Species 

 with Atelecyclus heterodon. By J. T. Cunningham, 

 M.A.> 



[Received February 15, 1898.] 

 (Plate XXI.) 



A complete account of the natural history of the common Edible 

 Crab is not in existence, and the naturalist who endeavours to 

 construct a life-history of the species from the separate observa- 

 tions recorded in zoological literature will find that direct 

 observations on this particular species are very scarce. A general 

 knowledge of the development of Brachyura has been obtained 

 from the partial study of various species, but the systematic 

 investigation of the diagnostic characters of the larval and 

 immature stages in the various divisions of the suborder has yet 

 much to accomplish. With regard to this species neither the 

 Zoaea, nor the Megalopa, nor the earliest post-larval form has 

 yet been figured and described in sufficient detail. 



The paper by E. Q. Couch in the Eeport of the Falmouth 

 Polytechnic Society for 1843 contains a brief description of the 

 Zoaea of this species, with a figure in the illustrating plate. A 

 special paper on the development of the Edible Crab was published 

 by the same author in the Eeports of the Penzance Natural 

 History Society for 1853-4-5. This paper is based on observations 

 made in 1852. The Zoaea is here again mentioned, and reference 

 is made to a figure of it as plate i. fig. 1 ; but I have been 

 unable to find any plat« or figure in the volume. The Megalopa 

 and the earliest post-larval stage are also described, but as it is not 

 my intention in the present paper to consider the larval stages, I 

 need only refer to the description of the first post-larval stage, 

 into which the Megalopa changes after ecdysis. It is stated that 

 in this stage the margin of the carapace was much more waved 

 than in the Megalopa ; the animal was now unUke any previous 

 state, but not at all like the adult. The lateral rim was indented 

 as in the adult, but instead of the oval form it was almost quad- 

 rangular ; the sides, instead of being rounded off as in the adxdt, 

 were perpendicular. 



Prof. S. I. Smith, in ' The Invertebrate Fauna of Vineyard Sound,' 



* Communicated by F. E. Beddard, F.R.S. 



