AMMOTHEIDAE 



99 



Remarks. This species is the largest that has been described up to the present. 



It is most closely allied to Ammothea striata, Mobius ; in both forms the chelophore 

 is large and the chela is perfect right up to the adult condition. The chief differences 

 between the two species are listed in the following table. 



Ammothea striata 



Proboscis long, slender, curved; 6 times 

 as long as wide and as long as trunk 



Scape subequal to chela and less than half 



of proboscis 



Second tibia the longest segment 



No large spines on proximal ventral 



margin of propodus, which is at least 



twice as long as claw 



Ammothea gigantea 



Proboscis stout, straight, 2\ times as long 

 as wide and not exceeding four-fifths of 

 trunk 



Scape twice as long as chela and three- 

 fourths of proboscis 

 Femur the longest segment 

 Two spines on proximal ventral margin 

 of propodus w-hich is only half as long 

 again as claw 



Ammothea tetrapora, n.sp. (Figs. 48, 49 and c^oa). 



St. 51. 4. V. 26. Off Eddystone Rock, East Falkland Island, from 7 miles N 50" E to 7-6 miles 

 N 63° E of Eddystone Rock, 105-115 m.; f. S. Large otter trawl: 2 $$, 2 ??. 



St. WS244. iS.vii. 28. 52'00'S, 62° 40' W, 253-247 m.;f.d. S.M. Commercial otter trawl : 

 I larvigerous ^ (holotype), i ?. 



Description of holotype. Trunk compact, lateral processes in contact or separated 

 by very narrow intervals proximally. Transverse body ridges prominent, each with a 

 high, narrow, conical median projection. 

 Cephalic segment considerably expanded 

 anteriorly, not quite as long as the sum of 

 the three posterior segments. Ocular tu- 

 bercle stout, scarcely higher than wide, 

 tapering to a point above the level of the 

 eyes ; anterior much larger than the pos- 

 terior eyes (Fig. 48). 



Proboscis straight; directed obliquely 

 downwards; widest at the base, then 

 sub-cylindrical, narrowing distally to a 

 blunt rounded apex; slightly more than 

 half as long as trunk.^ 



Abdomen elevated at an angle of about 45^ and reaching to distal end ot fourth lateral 



Droccss 



Chelophore. Scape short, club-shaped; distal width half the length. Chela small; 

 fingers reduced and no longer capable of meeting distally. 



Palp with only eight segments in all specimens; second approximately two-thirds 

 of fourth segment. The reduction in the number of segments may be due to fusion of 



Fig. 48. Ammothea tetrapora, n.sp. Female. Lateral 

 view of body with chelophore and palp: x 6. 



1 Measured dorsally. 



13-2 



