r8f)l).J A. ^Vlcock — Carcinologiral Fanna of India. 125 



or may bo interiiiediato in cliaracfcer. The gill-plumes vary in number 

 from 20 to 8 on either side. 



I follow Professor Boas, without hesitation, in placing the Dromiacea at the 

 base of the Brachyura; and J farther think that no one who has access to a good 

 spirit-collection of the two groups in question can read M. E.-L. Bouvier'a clever 

 paper, cited above, Sitr Vorigine Homarienne des Gruhes, without accepting the 

 opinion of the latter author— an opinion previously suggested, as the author states, 

 by Huxley — that the Dromiacea are the directly-connecting link between the Crabs 

 [Brachyura vera) and the liomaridce. 



The Dromiacea may be divided into two groups, whicli seem to me 

 to have something more than family value, namely, the Dromiidea and 

 the Homolidea, each of which has retained certain primitive characters 

 w^hile following its own line of evolution. 



Tribe I. Dromttdea. 



Dromiens, Milne Edwards, Hist. Nat. Crust. II. 168. 

 Bromidx, Henderson, Challenger Anomura, p. 2. 



Dromidce. et Dyiiomenidre, Ortmann, in Bronn's Thier Reich, V. ii. Arthropoda, 

 p. 1155. 



Carapace sometimes longer than broad, offen broader than long, 

 without linea anomurica. 



Eyes and aiitennuies almost always {Homolodromia is the only 

 exception) retractile into common orbito-antennulary pits, the lower 

 wall of which is formed about equally (1) by the basal joint of the 

 antennule itself, (2) by the basal joint of tlie antenna, and (3) by a 

 sub-orbital spine or dentiform lobe. 



These orbito-antennulai'y pits very often show traces of a sub- 

 division into two fossae, one for the antennule the other for the eye — tiie 

 boundary between the two fossas often being a tooth or a sort of fold in 

 the upper margin of the " orbit." 



Eye of the ordinary form, situated at the end of a short stout eye- 

 stalk, the basal joint of the eye-stalk being inconspicuous. 



Epistome triangular, its apex usually being in close contact with 

 tlie deflexed tip of the front. Vault of the palate of good depth. 



External maxillipeds usually opercular, sometimes subpediform. 



Fingers of the chelipeds generally shoi't, stout, channelled along 

 their opposed surfaces, and strongly calcified in their distal half. 



Sternum of the female traversed longitudinally, in part or in 

 almost all of its extent, by a pair of special grooves that sometimes end 

 in special tubercles. 



The abdomen of both sexes consists of seven separate segments. 

 Very often a pair of small lateral plates — the rudiments, probably, of 



