6 Memoirs of the Indian Museum. [Vor, IV); 
Pseudosquilla, Lysiosquilla and Coronida, while the other includes Odontodactylus and 
Gonodactylus. The condition of the ‘ischio-meral’ articulation of the second 
maxillipede or raptorial claw is the character on which this primary division is based. 
This character, indeed, appears to me to possess an importance which has not hitherto 
been appreciated and it shows that the affinities of Coronida, usually regarded as a 
close ally of Gonodactylus, have been to a great extent misunderstood. 
In the attempt to frame diagnoses of the four genera comprised in the first section 
of the family considerable difficulties are encountered, for although each genus 
has indeed a very distinct facies, several isolated forms exist which differ widely from 
the more typical members in structures that are either aberrant or annectant. A 
careful examination of species belonging to these four genera has not yielded me 
material for making any improvement in the classification hitherto adopted. The 
system employed is certainly unsatisfactory, but the groups are for the most part so 
readily distinguished that, even in the absence of good morphological characters, I 
cannot believe that their separation is unwarranted. 
The existing species of Stomatopoda are for the most part restricted to the 
warmer waters of the globe, but a few forms, such as Squilla mantis and S. desmarestt , 
have been found as far north as the British coasts, while others, such as Pseudosquilla 
stylifera, Squilla aculeata, S. gracilipes and S. armata, penetrate as far south as Chili 
and Patagonia, the last being also known from S. Africa and from New Zealand. 
Stomatopoda are exclusively marine, but one form, Squilla scorpio var. tmmacu- 
lata, extends for a considerable distance up the Ganges delta and must at times be 
brought in contact with water of quite low salinity. 
The large majority of the species are littoral or inhabit moderate depths; only 
the following eleven have been found below the 100 fathom line :— 
Squilla armata. Squilla massavensis. 
Squilla biformis. Squilla stridulans. 
Squilla gilesi.' Squilla tenuispinis. 
Squilla investigatoris. Lystosquilla insignis. 
Squilla leptosquilla. Lysiosquilla mataguesensis. 
Odontodactylus havanensis. 
The greatest depth at which any Stomatopod has been found is 370—419 fms. 
( S. leptosquilla—‘ Investigator ’ ). 
Stomatopods are essentially burrowing animals and many of the characteristic 
features of the order are adaptations for this purpose ; but they are not fossorial in 
the sense in which this term is generally used among the Decapoda. ‘The curious 
form and geniculation of the second maxillipedes must be admirably suited to an 
animal which lies in wait for its prey at the mouth of a burrow, while the small 
carapace and loose segmentation of the body-somites enables it to reverse its position 
in a narrow tunnel without difficulty. The peculiarly modified branchial system is 
' Caught in a trawl fished between depths of 80 and 110 fathoms. 
