31 



with certainty. Along the most proximal part of the inner margin a narrow area with a good 

 number of hooks is seen (fig. i e), probably a remnant of a lobus accessorius a little less developed 

 than in Sic. maldivensis. This area is found on a moderately thick, very oblong body, which 

 near the middle of the posterior side has two rather slender, subcylindrical lobes directed back- 

 wards and outwards, and each terminating in an extremely large hook; the outer of these 

 processes- is not improbably lobus armatus [la.), but the other must be an accessory lobe [lac^. 

 More distally on the posterior side of capitulum is seen a somewhat long, very slender lobe 

 directed mainly forwards and terminating in a rather large hook; this lobe (/^.) may answer to 

 lobus connectens in Sergestes. The capitulum terminates in a long, gradually tapering lobe, 

 lobus terminalis (//.), which is nearly spirally twisted and has on one side a very large number 

 of minute hooks; at the base of lobus terminalis a very short, truncate lobe projects forwards 

 and inwards and terminates in a very large hook; this last-named protuberance is perhaps lobus 

 inermis (?//.). — Pars astringens (fig. \d, a) is very broad, with the usual marginal row of 

 couphng hooks. 



Length of a large male 25 mm., of a small male 18.5 mm.; a very large female measures 

 31.5 mm. in length, but adult females are sometimes considerably smaller, about 25 mm. long. 



Remarks. — The male is instantly distinguished by the elongated antennular 

 peduncles and the peculiar petasma; the female can be separated from that of Sic. maldivensis 

 by the eyes, the two distal joints of the antennular peduncles, and the relative length of the 

 antennal squama. 



Distribution. — The localities hitherto known are enumerated above immediately 

 after the "Siboo-a" station. 



^t>"- 



Acetes H. M.-Edw. 



Diagnosis. — Body rather slender; general aspect nearly as in Sicyonella. Carapace 

 anteriorly with a short crest, armed with a single denticle or most frequently with two denticles, 

 and produced into a short rostral process. Supra-orbital and hepatic spines well developed. 

 Antennulse with second joint in the peduncle somewhat short; third joint in the female con- 

 siderably, in the male from considerably to twice or almost three times longer than the second ; 

 the lower flagellum in the male with the clasping organ as in Sergestes. Antenna; as in Sergestes. 

 Mandibles (PI. Ill, fig. 2c) mainly as in Sergestes; palp 3-jointed, with first joint very short, 

 second long and slender. Maxillulae (PI. Ill, fig. 2/) with both lobes well developed, but without 

 palp. Maxillae (PI. Ill, fig. 2g) with only a single undivided lobe, while the palp (/.) is well 

 developed, somewhat broad. First pair of maxillipeds (PI. Ill, fig. 2//) differ considerably in 

 shape from those in Sergestes \ the distal lobe is long, very oblong-triangular with the end sub- 

 acute; the palp is wanting, but exopod {ex.) and epipod {ep^ are well developed. Second pair 

 of maxillipeds (PI. Ill, fig. li) have the third joint long, much longer than the second and 

 about as long as the fifth, which is very long, while the sixth is short and slender; exopod 

 wanting; epipod and podobranchia well developed. Third_ pair of maxillipeds slender and long, 

 but always somewhat or considerably shorter than third pair of legs; each leg with only six 

 joints, as second joint is fused with the third; the two distal joints are undivided (PI, HI, fig. 2/'); 



