118 On the Anatomy o/' Darwinella Stevensoni. 



found chiefly in the mouth-apparatus ; but the lower antennse 

 also are abnormal, being quite destitute of the poison-gland 

 and urticating seta3 of the Cjtheridie. The mandible differs 

 much in structure from anj similar organ known to us in 

 either family. The first pair of jaws presents no special pecu- 

 liarity ; but in the second pair (which in the Cytheridte is 

 convertedj by the great development of the palp and atrophy 

 of the jaw-apparatus, into a simple foot with a mere trace of 

 its jaw origin in the form of a few bristles) we find a pediform 

 palp extremely well developed, combined with a large jaw, 

 which is armed with cutting-teeth and bears a fully developed 

 branchial plate. The palp of the second jaw Ave described in 

 our former paper as the " first foot ; " the mandibles and first 

 pair of jaws were also misunderstood, and indeed had not then 

 been seen except very imperfectly. The following description 

 gives, we believe, a true account of the structure of the 

 animal : — 



Antennse veiy short and stout, strongly armed with curved 

 claws and bristles : superior antennje six-jointed, ha^^ng all 

 the joints as broad as or broader than long, and beset with 

 short cm-ved seta3 ; inferior fom'-jointed, of nearly equal thick- 

 ness throughout : apex amied with four or five strong, slightly 

 curved, claws 5 entirely destitute of poison-gland or urticating 

 setfe, the place of which is occupied by a simple curved seta 

 of moderate length. Mandible (PL V. fig. 8) broad, truncate 

 at the free extremity, which is provided with six or seven 

 small, slender, spiniform teeth ; palp three-jointed, its basal 

 joint very wide, beset with a series of nine cmwed sette, and 

 giving attachment to a small subcrescentic lamina which is 

 fringed with about ten branchial filaments ; second joint 

 slender, nearly fom' times as long as broad, slightly curved and 

 dilated at the distal extremity, where it bears one long and 

 two small sette ; terminal joint more slender, about two thirds 

 the length of the foregoing, and bearing at its truncate apex 

 about six slender curved spines. Grasping portion of the first 

 jaw (PI. V. fig. 9) divided into four short setiferous segments, 

 and bearing a very large oblong palp, which is fringed above 

 with about twenty -fom- long branchial filaments, and has also 

 four long deflexed sette attached near its base. Second jaw 

 (PI. V. fig. 10) simple, short and wide, truncate at the apex, 

 and divided into several slender curved spines, bearing a large 

 three-jointed pediform palp and an ovate branchial appendage 

 of moderate size. Two pairs of feet of moderate length, five- 

 jointed ; the second pair much the longest, and having the last 

 joint armed with one long and two small curved seta ; first 

 three joints of nearly equal length, fourth and fifth respectively 



