IQIo. | S. Kemp: Notes on Decapoda. 177 
single large fold involving nearly one-third of the whole plate. 
When this fold is opened out the structure presents the appearance 
shown in fig. 3. 
Gennadas sordidus, sp. nov. 
(Plate xiv, figs. I—3.) 
St. 193.—North of the Laccadive Islands, 15° 11’ N., 72° 28’ 
45” E., 931 fathoms. One male, about 20 mm. 
St. 194.—Off the Laccadive Islands, 13° 47’ N., 72° 3’ 45” E., 
8g1 fathoms. One male, 24 mm. 
St. 198.—North-east of Ceylon, 8° 55’ N., 81° 17’ 30” E., 764 
fathoms. One male, 184} mm. 
The rostral crest does not differ appreciably from that of the 
preceding species. The antennary and infra-antennary angles are 
acute, the former being bluntly rounded and the latter sharp; the 
branchiostegal spine is very small. The distance between the 
cervical and post-cervical grooves, measured dorsally, is less than 
one-fifth the distance from the post-cervical groove to the hinder 
margin of the carapace. The mid-dorsal carina is inconspicuous 
behind the latter groove. 
The second joint of the antennular peduncle is very short; 
measured dorsally, it is less than half the length of the ultimate 
joint. The antennal scale is widest at the base; it is three times 
as long as wide and the outer margin terminates in a very small 
spine which does not extend as far forwards as the lamellar portion. 
The ultimate joint of the mandibular palp is shorter than the 
greatest width of the basal joint. In the second maxilla (fig. 3) 
the anterior lobe of the internal lacinia is short, not wider at the 
apex than at the base, and is little, if at all, narrower than the 
adjacent lobe of the external lacinia. In the latter lacinia the 
anterior lobe is about one and a half times as broad as the poste- 
rior. ‘The endopod is furnished with three curved spines near the 
narrow apex. 
The third joint of the endopod of the first maxillipede is about 
one and a half times the length of the second and the basal joint 
bears two or three stiff spines on the inner distal margin. 
In the first peraeopods the chela, which is about as long as the 
carpus, 1s about two-thirds the length of the merus. The chela of 
the second pair is two-thirds the length of the carpus and the. 
dactylus is equal to, or a trifle shorter than, the palm. In the 
third pair the carpus and merus are exactly the same length; the 
dactylus is as long as the palm, the whole chela being about half 
the length of the carpus. 
The median spines on the abdominal sterna are not prominent ; 
the sixth somite alone is dorsally carinate. The apex of the telson 
has much the same form as in G. alcocki. 
The petasma (figs. I, 2) is a rather complicated structure and is 
of much the same type as that of G. parvus, to which G. sordidus 
