96 THE VOYAGE OF H.M.S. CHALLENGER. 



largest of the specimens previously described, yet in many parts they have advanced 

 further in characteristic development (PI. XIIc. fig. 2). 



The ophthalmopoda are still long and Inarticulate, the stalk being long, slender and 

 cylindrical, the eye at its extremity being long and pear-shaped. 



The first pair of antennae affords evidence of its permanent form ; it has a peduncle of 

 three subecjual cylindrical joints which terminate in two short flagella, the inner of which 

 is slender and cylindrical, while the outer is flatter, broader and sharply pointed, and 

 on the convex side supports a few membranous cilia. 



The second pair of antennae is three- or four-jointed. The joints appear within an 

 outer case that is less articulated (PI. XIIb. fig. 4c). The first is short and cylindrical, 

 the second is long, flattened, and produced to a sharp point at the outer distal angle, the 

 third is short and cylindrical, and the fourth or last is flat, wide and produced to a point. 

 Within the outer integument, which is next to be shed, the structure exhibits the appear- 

 ance of a series of narrow lobes at the margin similar to those that we see in Scyllarus 

 and Arctus. The distance of the antennas from the oral apparatus is a little less than 

 half the length of the animal, and is occupied by distinctly formed hepatic lobes 

 arranged in a beautifully radiating series of branches. The mandibles are smaller than 

 in the preceding specimens, but the calcified tendon is long, slender, and feeble as 

 compared with those of the preceding specimens. I could detect no synaphipod, and 

 the apophysis is broad and of extreme tenuity. 



The first pair of siagnopoda (PL XIIb. fig. 4e) is two-branched, and lies closely 

 attached to the double lobed metastoma ; the two branches are tipped with three or four 

 hairs on each, which from their relative proportion appear like important spines ; the 

 second pair of appendages (fig. if) is in the form of a flat oblong plate, and corresponds 

 with that of the adult ; two small branches are also visible within a common outer sac. 



The next pair (fig. ig) is in a very incipient stage, and consists of a simple elongated 

 sac, without exhibiting any evidence of its future condition. An example of this is 

 likewise seen in Phyllosoma brevicorne, Leach, 1 which induces me to think that both 

 forms belong to a genus of Scyllaridae. 



The next pair of appendages (fig. 4/*), which I believe corresponds with the first pair 

 of gnathopoda, is developed in the form of a true leg ; it is only five-jointed, and carries a 

 long sub-cylindrical branchial sac attached to the coxa or first joint ; the second joint 

 is long and cylindrical, except for a small lobe or projection that exists on the outer 

 surface, one-third distant from the coxal joint ; the next two joints are subequal and of 

 the same diameter as the last, whereas the one or perhaps two terminal become suddenly 

 smaller and tapering, terminating in a fine spine : the next pair of legs corresponds to 

 the second pair of gnathopoda ; it is pediforrn, long, slender, and in all our specimens 

 is broken off more or less shortly ; attached to the coxa is a single subcylindrical branchial 

 sac. The next four pairs are also broken off, but the fragments remaining in the bottle show 



1 Milne-Edwards, Hist, des Crust., vol. ii. p. 482. 



