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



forward directed seta, which at the first glance may be taken for a third flagellum. 

 The true flagella are exceedingly elongate, nearly equalling the length of the whole 

 body. 



The antennal scale (see fig. 16), reaching but slightly beyond the second joint of the 

 antennular peduncle, is rather broad, of an oval form, and obtusely rounded at the tip, 

 with the outer corner jutting out as a well marked though rather small denticle. The 

 flagellum is very elongate, even slightly exceeding in length those on the antennulse. 



The oral parts of coiu'se could not be accurately examined in the single specimen 

 preserved. 



The maxillipeds and legs, as also the gills, would not appear to differ essentially from 

 those 23arts in Thysanopoda ohtusifrons. 



The eopulatory appendages to the first pair of pleopoda (fig. 19) are somewhat 

 similar to those in the last species. A few minor dift'erences may, however, be found 

 in the structural details. Thus, both the hook-shaped processes of the outer part 

 are quite simple, subulate, whereas in Thysanopoda ohtusifrons one is slightly dilated 

 at the tip and the other distinctly angulate at the l)ase. The appendages to the second 

 pair (fig. 20) agree almost exactly mth those in the above mentioned species. 



The telson (see fig. 17) is of moderate length, tapering uniformly towards the apex, 

 which is acutely pointed. The subapical spines (see fig. 18) are comparatively small and 

 scarcely at all divergent, as also quite smooth. Moreover, on the dorsal face of the telson 

 may be seen al)out six pairs of small denticles. 



The uropoda (see fig. 17), when extended backward, reach a little beyond the tip 

 of the telson, and exhibit between the plates a relation similar to that in Thysanopoda 

 ohtusifrons, the inner being appreciably shorter than the outer. 



Habitat. — The only specimen secured was brought up in the trawl from a consider- 

 able depth in the Celebes Sea, south of Mindanao, Philippine Islands — Station 213, 

 February 8, 1875 ; lat. 5' 47' N., long. 124° 1' E.; depth, 2050 fathoms; blue mud. 



In all probability the specimen in question did not actually enter the trawl at that 

 enormous depth, but most likely was taken l)y the net during its upward passage from 

 some intermediate stratum of the sea. 



28. Thysanopoda microphthalina, n. sp. (Woodcut, Fig. 3). 



Specific Characters. — Form of body comparatively slender. Carapace with a single 

 lateral denticle, projecting from the inferior margin far behind the middle ; anterior part 

 very slightly keeled above, and jutting forth as a well-marked acuminate rostrum. Caudal 

 segments smooth above, with epimera not very large. Last segment longer than 

 preceding ; preanal spine distinct unguiform. Eyes exceedingly small, rounded. 

 Antennular peduncle strong, with a densely hispid lobe projecting from the basal joint 



