146 HISTORY OF BRITISH CRUSTACEA. 
Gen. 49. MACROMYSIS* 
Upper antennse armed with a scale. First, second, and 
fifth segments of the abdomen bearing fins like the Mysis , 
third and fourth with the peduncles biarticulate, and each 
peduncle giving off two branches ; the outer branch of 
the fourth very long and slender, semi-articulated. 
Macromysis longispinosus, Goodsir. — Whole body of 
a dark yellowish or greenish colour. Beak very short, but 
sharp-pointed; upper antennal scale of the same length as 
the last joint of the peduncle ; lower antennal scale twice as 
long as the peduncle, three-quarters of an inch long. 
Firth of Forth (Goodsir). 
Macromysis brevispinosus, Goodsir.— Whole body of 
an opaque white, with a row of black spots down the back 
of the abdominal segments. Beak of considerable length, 
but not sharp ; upper antennal scale not so long as the pe- 
duncle; lower antennal scale four or five times as long as 
the peduncle. Length an inch. 
Firth of Forth (Goodsir) ; Bangor, County Down (W. 
Thompson) . This species and the preceding were discovered 
* Themisto, Goodsir. — Edin. New Phil. Journ. 33. A name previously 
employed by Guerin Menevilie for a genus of Crustacea. 
