by Rev. T. R. R. Stebbing. 15 
After all the pains devoted to this genus by de Man, Ortmann, 
Alcock, Miss Rathbun, and others, an unenviable task awaits the 
investigator qualified and willing to examine the claims of its numerous 
nominal species. After noting ‘The common practice of using the 
larger cheliped of the male for the discrimination of the species,” with 
the caution that this organ is apt to change greatly with advancing 
age, the indefatigable Alcock, adds, ‘‘I must also confess here that 
the synonymy of species has defied me.” With this confession, as will 
be seen, I can heartily sympathize. 
The mouth-organs show one or two peculiarities to which attention 
may be directed. The mandibles are comparatively small, with the 
third joint of the palp rather iong. ‘The first maxillee have the inner 
plate of unusual size, broader than long, much broader than the outer 
plate, the rounded summit surmounted by stiff spines of which the 
central are the longest. I suspect that de Haan’s figure represents 
only the thick basal portion of this plate, as in my first dissection I 
found it broken precisely in that manner. The two-jointed palp is 
weak. The second maxille have the large chitinous bow, from which 
the two lower plates are produced, closely fringed with very long sete. 
The vibratory lamina, omitted by de Haan, is very fragile. In the 
first maxilliped the large joint is flat-topped, the rest of the endopod 
long and folded. In the second maxillipeds the long fourth joint, 
besides the fringe of long sete, has, on the distal portion a special 
_armatyre of sete varying in length but with little saucer-like tips 
suggestive of some adhesive function. In the species figured the 
terminal joint has a similar apical group, but this if present was 
inconspicuous in our U. arcwatus. Vhe third maxillipeds are well 
known for the great size of the third joint, nearly as broad as long, 
and about three times as long as the fourth joint. 
The stomach of Uca bellator (Adams and White) is described by 
Nauck in‘his dissertation, ‘‘ Das Kaugezust der Brachyuren,” p. 21, 
Uca arcuatus (de Haan). 
1835. Ocypode (Gelasimus) arcuata, de Haan, Crust. Japon, decas 
2, pp. 26, 53, pl. 7, fig. 2, ¢, and pl. B (mouth-organs). 
1852. Gelasumus arcuatus, Milne-Edwards, Ann. Sci. Nat., ser. 3, 
zool., vol. xviii, p. 146, pl. 3, figs. 8, 8a. 
1905. Uca arcuata, Stebbing, S. Afr. Crust., pt. 3, p. 40 (with 
synonymy). 
To these references I should be inclined to add Gelasimus vocans, 
Milne-Edwards, in the work above cited, p. 145, pl. 3, fig. 4, which 
