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1973: | S. Kemp: Crustacea Stomatopoda of the Indo-Pacific Region. 5 
*spinosissimus, Pfeffer. tanensis (Fukuda). 
spinoso-carinatus, Fukuda. trispinosus, Dana. 
stoliurus (Muller). tuberosus, Pocock. 
The species known from the Atlantic and Mediterranean and from the Pacific 
Coast of America are separately listed at the end of this paper with a few of the more 
important references and synonyms (p. 200). 
The exact relations of the Stomatopoda with other groups of Crustacea present 
a difficult problem. ‘The existing forms show a high degree of specialization coupled 
with several features that at first sight seem primitive. Of the latter the most striking 
is the freely movable ophthalmic and antennular somites, but this is now regarded 
as a secondary character and must also be taken as evidence of specialization. 
With the views which Calman has expressed on the affinities of the group I am in 
entire agreement and his conclusion (1909, p. 331) that it seems most probable that 
“the Stomatopoda are a lateral offshoot from the main stem of the Malacostraca, of 
which, in the absence of connecting links, it is as yet impossible to determine the 
exact relations,’’ will, I believe, meet with general acceptance. 
The oldest known fossil Stomatopoda have been found in the Jurassic beds of the 
Solenhofen and have been referred to the genus Scuwlda. Little information of the 
really satisfactory nature is available concerning these forms; but there is, I believe, 
enough to warrant the creation of a separate family for their reception (see p. I5). 
The species are for the most part ornamented with an elaborate sculpture in no respect 
less remarkable than that of some of the existing forms of Squtlla and Gonodactylus, 
though of an entirely different type, and it is clear that they also must have attained 
a high degree of specialization. It is to be hoped that specimens will soon be found 
which will provide satisfactory material for a study of the appendages. In parti- 
cular, information regarding the form of the second thoracic appendage, which attains 
such a monstrous development in the Squillidae, would be most valuable. This limb 
has been found in an excellent state of preservation in fossil examples of Sguwalla, but 
it has never been satisfactorily demonstrated in Sculda. Seeing that in the former 
genus it appears to be well adapted for preservation in stratified rocks it is difficult, 
on the view that it possesses a similar development, to explain its absence in the 
latter. 
Species of Squilla have been obtained in the Cretaceous and in the London Clay 
and other tertiary deposits, and in all structural details which have been studied they 
appear to bear a close resemblance to existing representatives of the genus. 
Brooks held that the forms which he included under the genus Protosquilla (here 
regarded merely as a section of Gonodactylus) were the most primitive that persist ; 
but this view has been severely criticized by Hansen and is not now generally 
accepted. My own observations lead me to conclude that it is among the species of 
Squilla that the most primitive forms are to be sought ; but the precise relationships 
of the several genera are by no means easily traced. 
The genera fall without difficulty into two groups, the one comprising Squil/a, 
