SIVADO. 315 



racters by which this eminent carcinologist distinguishes 

 the latter supposed species can be considered as constant, as 

 I have seen British specimens which vary considerably in 

 the degree of ciliation in the parts from which he deduces 

 his distinctions. It is, finally, very evident that the figure 

 of Guerin in his " Monographic," imperfect and unsatis- 

 factory as it is, and which he refers to P. Sivado, belongs 

 to our British species ; and the result of all these conside- 

 rations in my mind, is the full conviction that we are at 

 present acquainted with but one species of this genus : I 

 have therefore retained E/isso^s original specific name of 

 Sivado. It now remains that I should state what is known 

 about this species as a native of Britain. It appears pro- 

 bable, from the following extract of a letter from Dr. Leach 

 to Mr. Baker of Bridgewater, that the first British speci- 

 men known was in the collection of Mr. Sowerby ; and it 

 also appears from the same passage that Mr. Baker had 

 himself sent another individual of this species to Dr. Leach 

 with some other Crustacea and insects. Dr. Leach writes, 

 " I cannot refrain from noticing two species which give me 

 the most pleasure. The one is a species of the genus 

 Pasiphaa of Savigny. I have seen a specimen of this genus 

 in Mr. Sowerby's collection, and I believe it to be the same 

 species." Subsequently Mr. Baker obtained several others, 

 taken, I believe, in the Bristol Channel, which are now, 

 through his kindness, in my possession, and I have lately 

 received from Mr. M'Andrew, two individuals, a male 

 and a female, taken by him in the Irish Channel, the 

 latter having the ova excluded and attached to the ab- 

 dominal false feet. It would appear by the following 

 notice in the fifth vol. of the " Annals of Natural His- 

 tory," by Mr. W. Thompson, that the specimen in the 

 British Museum was originally taken on the coast of Ire- 



