29 



The epistome is triangular or truncate-triangular, and is well delimited from 

 the palate. 



The buccal cavern is quadrilateral, but is usually broader in front than 

 behind. The external maxillipeds may ])o pediform, or sub-pediform, or com- 

 pletely opercular. 



The last pair of legs arc dorsal in position, and, with few exceptions, are 

 prehensile slender and reduced in size, or even sometimes rudimentary. The 

 penultimate pair sometimes resemble the last pair. 



The abdomen in both sexes is large, and usually consists of seven separate 

 seo-ments : in the male it has the usual anterior two pairs of modified copulatory 

 appendages, behind which, very occasionally, are 3 other pairs of rudimentary 

 appendages : in the female it has the usual four pairs of ovigerous appendages 

 and, in addition, a pair of smaller uniramous appendages situated on the first 

 segment. 



The oviducts pei'forate the coxopodites of the antepenultimate pair of legs, 

 and the seminal ducts perforate the coxopodites of the last pair of legs. 



The gills are usually phyllobranchife, but may be trichobranchias or may be 

 intermediate in character : they vai-y in number from 20 to 8 on either side. 



All the Dromides are marine and many of them are found only in deej) 

 water. 



I have proposed to divide the Drouiiacea into two tribal groups, namely : — 



I. Dromiipea, in which the carapace has no liiiesi anomuricse, the eyes and 

 antennules are almost always retractile into orbito-antennular pits, the Gth pair 

 of abdominal appendages are commonly represented by a pair of small plates 

 intercalated between the Gth and 7th abdominal somites, and the sternum of the 

 female is traversed in more or less of its extent by two obliquely-longitudinal 

 grooves. 



II. HoMOLiDEA, in which linrcS aiKiiii urine are usually present, the eyes and 

 antennules arc not retractile into ca^uties, the Gth pair of abdominal appendages 

 are not in any Avay represented, and the sternum of the female is not traversed 

 by any special grooves. 



I. Dkomiiuka, Alcock. 



Vrnmicns, Jlilne Edwards, Uist. Nat. Crust. 11. lliS. 

 DromicJa;, Henderson, Challenger Anomnrn, p. 2. 



Dromidx et Dynomenidw, Ortmann in Bronn's Thicr-Reicli, ilalacostraca, p. 1155. 



Promiiii.E et Dynomcnin^; A. Slilne Edwards & E. L. Bouvier, Crust. Decap. HirondoUe et PrinccBSe .\iice 

 Monaco, 1899, p. 9. 



Dromiidii', Alcock, .Tourn. Asiatic Soc. Bengal, Vol. LXVIll, pt. 2, 1S',(9, p. 12."). 



Carapace sometimes longer than broad, often broader than long, without 

 liiK'X auoiiiurica;. 



