Bull. Mus. natl. Hi.et. nat., Paris, 4" s6r., 13, 1991, section A, n" 3-4 : 45'7-481. A small collection of deep water spongecrabs (Brachyura, Dromiidae) from French Polynesia, including a new speciesof SphaerodromiaAlcock, 1899 by Colin L. Mclev Abstract. - This paper reports on a small collection of sponge crabs (Brachyura : Dromiidae) from French Polynesia, mostly collected by the Service Mixte de Contr6le Biologique des Arm6es (SMCB) during 1984-1990 using baited traps from depths of 100-1120m. These crabs came from depths between 190-450m. In addition one soecimen came from 3-5m on a coral reef near Moorea. The collection includes Cryptodromiopsis tridens Borradaile, 1903a, Petalomera wilsoni (Fulton and Grant, 1902), and Sphaerodromia ducoussoisp. nov. With the description of the new species,the opportunity is taken to review the genus Sphaerodromia which now contains four species : S. kendalli (Alcock and Anderson, 1894), ,t. nux Alcock, 1899r, S. brizops Mclay and Crosnier, 1991, and S. ducoussoi sp. nov. S. lethrinusaeTakeda and Kurata, 1976, does not belong in this genus. The genus Sphaerodromia must be considered the most primitive known genus of the Dromiidae and comparison with Dynomene devaneyi Takeda, 1977 (Dynomenidae), shows many similarities. The only substantial difference is that Sphaerodromia has phyllobranchiate gills while those of D. devaneyiare transitional between trichobran- chiate and phyllobranchiate. An hypothesis about the nature of the ancestral dromiids is presented. The generic position ofeach ofthe other dromiid species from French Polynesia is considered and the need for generic revision of the Dromiidae, employing a wider range of characters, is emphasized.The characters which should be used include : the presence or absence of epipods in the chelipeds and legs, extent of development of the uropod plates on the abdomen, features of the orbit and antenna, male pleopods, the abdominal locking mechanism, female sternal grooves and the development of spines on and around the dactyls of the legs. Indications of how some of the dromiids should be rearranged are given. The new records and species add to the known dromiid fauna of French Polynesia Cryptodromia can'aliculata Stimpson, 1858 and C. coronata Stimpson, 1858 and bring the total to five species. The biogeographic relations of these speciesare similar to those already identified by Fonnsr and GrnNor (1962) for the other French Polynesia Brachyura. R6sum6. - Cet article concerne une Detite collection de Dromiidae provenant de la Polvndsie franqaise, recolt6s pour la plupart par le ServiceMixte de Contr6le biologiqu'e des Arm6es (SMCtil qui, entre 1984 et 1990, a effectu6 de nombreuses p€ches au moyen de casiers, d des profondeurs comprises entre 100 et 1120m. Les crabes 6tudi6s ici ont 6t6 r6colt6s entre 190 et 450m. Il s'y ajoute un sp6cimen captur6 entre 3 et 5 m sur un r6cif prds de Moorea. La collection comprend Cryptodromiopsis tridens Borradaile, 1903, Petalomera wilsoni (Fulton et Grant, 1902) et Sphaerodromia ducoussoi sp. nov. La description d'une nouvelle espdcede Sphaerodromia fournit I'occasion de revoir ce genre qui renferme maintenant quatre espdces; 5. kendalli (Alcock et Anderson, 1894), S. nux Alcock, 1899r, S. brizops Mclay et Crosnier, l99l et S. ducoussoi sp. nov. S. lethrinusae Takeda et Kurata, 1976 n'appartient pas d ce genre. Le genre Sphaerodromiapeut €tre consid6r6 comme le plus primitif des genres de la famille des Dromiidae et une comparaison avec Dynomene devaneyi (Dynomenidae) montre de nombreuses similitudes. La seule diff6rence importante est que Sphaerodromiapossddedes phyllobranchies tandis que D. devaneyi pr6sente des branchies interm6diaires entre des trichobranchies et des phyllobranchies. La position g6n6rique de chacune des autres espdces de Dromiidae de Polyn6sie frangaise est examin6e et la n6cessit6 d'une r6vision des Dromiidae, faisant intervenir un 6ventail plus grand de caractdres, est