Carcinological Fauna of India. 127 
In comparing the above synopses of characters it will be seen that the Dromidea 
as a whole have developed along Brachyurons lines in respect of the antennal 
flagella, orbits, external maxillipeds, and shape of the carapace, but have kept near 
to the primitive (Homarid) branchial arrangements. Whereas the Homolidea as a 
whole show a tendency to approach the higher Brachyura in the reduction of the 
branchiz, but have not departed much from the primitive (Homarid) type in the 
form of the antennal flagella, external maxillipeds and very imperfect orbits. 
Tribe I. DROMIIDEA. 
The Dromiidea which, notwithstanding the more Brachyurous form 
of the carapace of their best known representatives, are as a whole more 
primitive than the Homolidea may be divided into three families— 
Homolodromidx, Dynomenidx and Dromidw—eharacterized as follows :— 
Family I. Homotopromipz. 
Carapace longer than broad, convex in both directions, the true 
cervical and the branchial grooves both present, 
Front cut into two prominent teeth, between which, but on a much 
lower plane, a third small tooth is sometimes present. 
Antennal flagella longer than the carapace. 
External maxillipeds with a marked pediform cast. 
Chelipeds equal, slender, though stouter than the legs. 
First two pair of legs much longer than the chelipeds: last two 
pair much shorter than the first two pair, subdorsal, prehensile. 
The abdomen in both sexes consists of 7 separate segments: there 
are no lateral platelets intercalated between the 6th and 7th segments. 
The gills are trichobranchiw, or are intermediate between trfcho- 
branchiz and phyllobranchie: the gill-plumes are very numerous— 
there may be as many as 20 on either side. 
Epipodites are present on the chelipeds and first two or three pairs 
of legs. 
The sternal grooves of the female are short, ending at the level of 
the genital openings. 
To this family belong the following genera :~— 
1. Homolodromia, A. Milne Edwards, Bull. Mus. Comp. Zool., VIII. 1880, 
p- 33: Recueil de Fig. de Crustacés Nouveaux, pl. 39, fig. 2. 
2. Dicranodromia, A. Milne Edwards, Bull. Mus. Comp. Zool., VIII. 1880, 
p. 31: Recueil de Fig. de Crust. Nouv. pl. 10. 
3. *Arachnodromia, Alcock, seq. 
Family II. Dynomenip#, Ortmann. 
Dynomenidzx, Ortmann in Bronn’s Thier Reich, V, ii., Arthropoda, p, 1155. 
Carapace variable, either longer than broad and convex, or broader 
577 
