146 Memotrs of the Indian Museum. [Vor. IV, 
median. ‘The mandibular palp is two or three-segmented.' ‘The posterior margin of the sixth abdominal 
somite is straight or slightly convex in dorsal view. The basal segment of the outer uropod extends far 
beyond the point of articulation of the ultimate segment, and the spines on the external margin of this 
projecting portion are in most cases very distinctly recurved. ‘The inner uropod is always abnormal in 
shape ; it is usually more or less crescentic when seen from above, or may be strongly arched in lateral 
view. ‘The setae are restricted to only a portion of the margin or may invest all the edges and the greater 
part of the upper surface as well. 
This highly-specialized and peculiar group includes six species, all of which seem to be very rare. They 
are G. herdmani, drepanophorus, brevisquamatus, fimbriatus, spinosocarinatus and furcicaudatus. ‘The first 
two possess a closer affinity with the preceding section than the rest. 
Group III.-—The anterior margins of the carapace do not slope forwards on either side of the rostrum 
and the antero-lateral angles are consequently not in advance of the level of the rostral base. The rostrum, 
typically, is trispinous; the antero-lateral angles are produced to sharp spines similar to the median, but these 
in rare cases are only acute. ‘The mandibular palp comprises two segments only.” The posterior margin of 
the sixth abdominal somite, when seen in dorsal view, is distinctly convex in the middle. The basal seg- 
ment of the outer uropod articulates terminally with the ultimate segment and is armed with straight mov- 
able spines on its external edge. The inner uropod, as in Group I, is normal in shape and in its investment 
of setae. 
This group includes nearly all the species which Brooks referred to Protosquilla. It comprises G. tris- 
spinosus, stoliurus, excavatus, folint, brookst, spinosissimus and numerous allied forms. 
Grour IV.—The anterior margins of the carapace slope forwards on either side of the rostrum, so 
that the antero-lateral angles are well in advance of the rostral base. ‘The rostrum is trispinous, but the 
lateral spines are not so well developed as in most species of the two preceding groups. The mandibular 
palp is wholly absent. ‘The posterior margin of the last abdominal somite is straight in dorsal view. The 
basal segment of the outer uropod projects posteriorly a little beyond the insertion of the ultimate seg- 
ment and bears a series of straight spines on its outer margin. Both the inner uropod and the terminal 
segment of the outer uropod are provided with setae only on the distal half of their outer margins ; the 
inner margin in each case bears sharp spines. 
This group ineludes a single species only ; G. acanthurus, 
Of the thirty-two species here recognized, twenty-eight are restricted to Indo- 
pacific waters. Three, G. oerstedi, G. festae, and G. folini, are known only from the 
Atlantic, while G. glabrous, a widely distributed Indo-pacific form, is recorded from 
the Mediterranean. 
Brooks (1893, p. 353) has given a most valuable account of the habits of 
Gonodactylus * in the Bahamas, where he found that the animals made burrows in 
hard stone. He gives most interesting details of their cannibalistic propensities and 
of the manner in which the female tends the egg-masses. Of the habits of the Indo- 
pacific species practically nothing is known ; they seem to prefer rough ground and 
coral reefs and possibly all of them burrow in coral or rock as in the case of the 
! Two species only have been examined; the palp is three-segmented in G. herdmant, two-segmented 
in G. furcicaudatus. 
? Six species examined. 
® Brooks calls the species G. chiragra, but the specimens doubtless belong to G. oerstedi, Hansen. 
