TETROMxiTUS. 
171 
Ain onyx denticulatus, Spence Bate. — Posterior and 
lower end of the ninth and tenth segments from the head 
produced into a tooth-like process. 
Moray Birth (Rev. Mr. Gordon) ; Banff (Mr. Edwards). 
Gen. 68. TETROMATUS, Sjoence Bate . 
Head projecting forwards into a snout; eyes four, not 
compound ; upper antenna in advance of the lower, proceed- 
ing from the end; lower situated far behind. Mandible 
with palpus ; jaw-feet imperfectly prehensile. 
Tetromatus typicus, Spence Bate. (Plate X. fig. 4.) — 
Head and front segments much compressed ; upper antenna 
half as long as the lower, the latter the length of the ani- 
mal ; hind margin of the tenth segment from the head not 
ornate. 
Moray Eirth (Rev. Mr. Gordon) ; Plymouth (Messrs. 
Smyth and Bate) . 
Tetromatus Bellianus, Spence Bate. — Upper antenna 
not so long as the peduncle of the lower ; hind margin of the 
tenth segment from the head ornate. 
Moray Birth (Rev. Mr. Gordon) ; Plymouth Sound (Mr. 
Spence Bate). 
