CRUSTACEA. 



93 



GEOUP STOMAPODA. 



MYSIBM. 



Genus, Mysis. — Lats. 



Legs terminating in a multarticnlate extremity supporting 

 a second multartieulate branch attached 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 Edwards, Hist, des Crust., t. ii, ^.457. 



M. Spinulous. — Couch's 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 Griffith slze. — Bell, Stalk-eyed 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 Palccmon 

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

 approximates. 



Gentjs, Thysanapoda. 



Branchia external and pendulous, branched, legs having the 

 secondary branch short. 



Thysan apod a Couchii. — bell, Stalk-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. " Tho 

 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 tho Lizard ; and I have 

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



I 



