174 Records of the Indian Museum. [VoL. V, 
pairs of peraeopods, a considerable amount of variation is some- 
times to be found. 
Three of the species in the collection are regarded as new, an 
interesting variation in the petasma of G. scutatus, Bouvier, is 
noticed and a fresh description is given of G. cavinatus, Smith, a 
remarkable form which combines in one species the characters both 
of Gennadas and of the allied genus Benthesicymus. 
The number of specimens examined is unfortunately small and 
this is doubtless due to the fact that the ‘ Investigator’ collections 
were made almost entirely by means of trawls fishing on the 
bottom. The species of Gennadas, as far as is at present known, 
are entirely pelagic in habit and their occasional appearance in 
bottom hauls is explained by the fact that they are sometimes 
caught while the net is being hauled to the surface. 
All the species mentioned in this paper possess podobranchs 
on the first three pairs of peraeopods and are in consequence 
members of the genus Gennadas, sensu stricto. 
The measurements given represent the total length, and were 
taken from the apex of the rostrum to the tip of the telson, with 
the animal extended as nearly as possible in a straight line. 
Gennadas alcocki, sp. nov. 
(Plate xiii, figs. 5-8.) 
St. 111.—Bay of Bengal, 12° 50’ N., 90° 52’ E., 1,644 fathoms. 
One male, 36 mm. 
St. 103.—Bay of Bengal, 15° 14’ N., 81° 9’ E., 1,260 fathoms. 
One female, about 25 mm. 
St 108 Off (Cs Comorin,, 7° 4° N. 767 347 15 Eb 043 fath= 
oms. One male, 34 mm. 
St. 309.—Near the Andaman Islands, 10° 9’ N., 93° 2’ 15” E., 
765 fathoms. One male, 34 mm. 
The rostrum is well elevated above the dorsal carina of the 
carapace and bears the usual small tubercle behind the dorsal 
tooth. The antennary and infra-antennary angles are acute and 
the branchiostegal spine is small but evident. The cervical and 
post-cervical grooves of the carapace are well marked; dorsally, 
the distance between them is only about one-fifth of the distance 
from the post-cervical groove to the hinder margin. The median 
carina is visible throughout the length of the carapace. 
The second joint of the antennular peduncle, measured 
dorsally, is fully two-thirds the length of the ultimate joint. The 
antennal scale (fig. 7) is a little more than three times as long 
as wide; the outer margin is somewhat convex and termi- 
nates in a spine which extends beyond the narrow apex of the 
lamella. 
The ultimate joint of the mandibular palp varies in length, 
but is, in all cases, shorter than the greatest width of the basal 
joint. In the second maxilla the anterior lobe of the internal 
