REPORT ON THE CRUSTACEA MACRURA. 



kind, but less capable of resistance than the other two. These three somites therefore 

 support each other, and by acting in concert when drawn up beneath the ventral surface 

 of the animal, and then forcibly struck out, must be capable of inflicting a very severe 

 wound. 



There seems to be a curious correlation between the length of the telson and the length 



Fig. XV. — Glyphocrangon, T, fifth somite of the pleon ; V, sixth somite of the pleon ; Z, telson. 



of the rostrum. When the telson is long and slender the rostrum is also long and slender, 

 and when the telson is short the rostrum is never long, and is frequently very short, or 

 wanting, as in Crangon and the Synaxidea. The rostrum by its length appears to afford 

 protection to the ophthalmopoda and the antennas, and the telson, by its rigidity and 

 length, likewise affords protection to the lateral appendages of the rhipidura. 



(ZOOL. CHALL. EXP. — PART LII. 1888.) 



Fff r? 



