222 Mr. C. Spence Bate on Synaxes. 



The second somite dorsally underlies and laterally overlies 

 the first somite with a small flat projecting process, at the base 

 of the upper part of which is the articulation on which the 

 somite moves. In the central dorsal line is a narrow eleva- 

 tion or ridge, which is low and smooth and repeated on the 

 three following somites. Laterally the coxal plates are fused 

 with the somite very perfectly ; and each successive somite 

 articulates with the preceding by a small cup-like process, 

 which receives the extremity of a small rounded tubercle that 

 is situated in a notch in the posterior margin of the preceding 

 somite. 



The sixth somite is smaller than the others, and dorsally 

 smooth, and supports laterally and posteriorly an appendage 

 with two foliaceous branches. 



The telson is anteriorly calcareous, and posteriorly folia- 

 ceous. 



The eyes are small, and appended to the extremity of short 

 peduncles that are laterally connected with the ophthalmic 

 nerve tlirough a long narrow foramen formed by the under 

 surface of the rostral projection impinging against the upper 

 surface of the first and second joints of the second antennge, 

 which is produced so far inwards and outwards as to meet on 

 each side in a sharp process near the median line, close under 

 the apex of the rostral projection. 



The first pair of antenna, in consequence of the formation 

 of the basal joint of the second pair, is forced downwards, 

 and, when viewed in a lateral or frontal direction the first 

 pair of antennge, is seen beneath ihe second pair. It is three- 

 jointed and slender ; the first joint is long and slight, the 

 second and third are subequal and about half the length of the 

 first, terminating in two small flagella that are not longer than 

 the third joint. 



The second pair of antennge has the first and second 

 joints solidly fused with the metopus (face) or ventral surface 

 of the cephalon, so that three joints only are free. The basal 

 joints are so closely fused together that it is impossible to de- 

 termine their limits, beyond the fact of the position of the 

 phymacerite. The third joint is broad and excavated on the 

 inner and lower side to allow space for the first pair of an- 

 tennge, which the second pair partially overrides. The fourth 

 or penultimate joint is broad and short; and the ultimate 

 is about the same length, and with a short obtuse spine 

 on the outer distal angle. This last carries a stifi" and strong 

 multiarticulate flagellum, each articulus of which is fringed 

 with small bristle-like hairs. 



The mandible is robust, smooth on the incisive margin, 



