28 MEMOIR II. 



fin spotted with the same colour mixed with black. Dis- 

 covered by Dr. Leach on the Scottish coast in the Frith 

 of Forth near to Leith, where it was observed in great 

 abundance in the pools left by the tide. Found with fry 

 from the middle of June to the middle of July, the females 

 being more numerous than the males. Length \.\ inch. 

 Dr. Leach refers to this species, the Cancer flexuosus of 

 MuUcr (Zool. Dan. p. 34 t ^^), as well as Cancer multipes 

 of Montagu, both of Avhich are more probably referable 

 to the following, viz. 



Mysis Chamaleon * Plate 2, fig. 1 to 10. This species 

 resembles the former so much in size, and in some of its 

 characters, that it would appear to have been hitherto 

 confounded with it. Mysis Chamseleon differs however 

 obviously, in the form of the outer laminae of the tail, 

 which are but very slightly taper, and very obtuse at the 

 point ; the notch in the middle lamina, is furnished with 

 a margin of smaller spines than those on the outer edge 

 which ends on each side in a straight and stout spine ; the 

 adjoining edge of the innermost of the lateral scales, is also 

 spinous, although the spines are not very obvious, from 

 the plumose cilise which cover them. The anterior scales 

 are very long, nearly linear, obliquely truncated at the 

 end, with a spine at the outer angle of the truncation, and 

 are ciliated 07ily along the inner edge and at the extremity. 

 The Clypeus ends in an obtuse point, and has a short spi- 

 nous point anteriorly at the sides. 



Nothing can shew the fallacy of colour in distinguishing 

 the species, more clearly than the variety of tints which 

 Mysis Chameeleon assumes, as it occurs here in the river 

 Lee and Harbour of Cove, and which have suggested its 

 trivial name ; in the upper part of the river below the 

 City of Cork, it occurs ot different shades of grey, inclin- 



* Mysis, Cauda lamella intermedia margine spinulosa, apice acute em ar- 

 giuata ; lamellis exterioribus suhtruncatis : lameliis auterioribus oblique 

 truncatisj intus ciliatis. 



