488 A CORNISH FAUNA. 



GEOUP STOMAPODA. 



GrENUs, Mysis. — Lats. 



Legs terminating in a multarticulate extremity supporting 

 a second multarticulate branch, attaclied to the "coxa," or first 

 joint. Female carrying the ova beneath the body in a pouch. 



Mysis chameleon. — (Opossum Shrimp.) — V. Thompson, Zool. 

 Research, p. 27; Milne Edivards, Hist, des Crust., t. ii, p. 457. 



M. Spinulous. — GoucNs Cornish Fauna, p. 80. 



" Common in summer, when it draws near the shallows from 

 deep water. It also enters rivers in multitudes, forming a long 

 line of migrations, at which season it is much devoured by the 

 trout. Its English name is taken from its habit of carrying the 

 eggs in a receptacle under the body, until they are hatched, as in 

 the analogous genus of quadrupeds, the opossum tribe. 



There are other species as well as the nearly allied genus 

 Cynthia on our coast, but they are here omitted for want of 

 a recent opportunity for comparison. 



Mysis griffithsi^. — Bell, Stalheyed Crust, p. 342. 



We have taken this supposed species, but I feel assured that it 

 is only the younger stage of a macrurous form, probably Palcemon 

 or Grangon, the young of either genus of which it closely 

 approximates. 



Genus, Thysanapoda. 



Branchia external and pendulous, branched, legs having the 

 secondary branch short. 



Thysanapoda Couchii. — Bell, Stallc-eyed Crust, p. 346. 



This species was described by Professor Bell from specimens 

 sent to him by " Mr. Couch, who obtained them from the Cornish 

 coast from the stomach of a mackerel, which appeared to have 

 been making a feast of this rare and interesting little Crustacea." 

 The author adds " The following account has been kindly 

 furnished me by that gentlemam, and shows that it can scarcely 

 be considered as an ordinary inhabitant of our coasts. "The 

 mackerel from which the curious shrimps Thysanopoda were 

 taken, were caught almost at mid-channel, or almost ten leagues 

 from us, perhaps seven or eight south of the Lizard ; and I have 

 not seen any since, although I am much in the habit of search- 



