522 REV. T. R. R. STEERING ON CRUSTACEANS [May 22, 



curved and compressed. The tail of the male is 6-jointed and 

 deeply notched on each side about tbe middle. The outer pedi- 

 palps, as in Hymenosoma, are covered on the outside with short 

 hairs." 



It seems a fairly clear and innocent account, till you begin to 

 work with it. White* assigns to his subgenus two species, the 

 second being Hymenosoma depressum Jacquinot, which in 1852 

 was referred to Hymenicus by Dana. Miers, however, in 1876 

 informs us that the specimens referred by White to Jacquinot's 

 species are distinct from it, and he names them Elamena ivhitei. 

 White's first species is Halicarcinus planatus, with the synonymy 

 Leucosia planata Fabricius, Hymenosoma leachii Guerin, and 

 Hymenosoma tridentatum Jacquinot. This last synonym is accepted 

 without reserve by Milne-Edwards in 1853, by Heller in 1868, and 

 Tozzetti in 1877, all of whom quote it accurately from Jacquinot's 

 plate as Hymenosoma tridentata. It is accepted with doubt by 

 Dana in 1852, by Miers in 1876, and by Haswell in 1882. Miers 

 drops the query in 1879, and inferentially in 1886. Lucas in 

 1853 describes under the name " Hymenosoma ? tridentatum," not 

 Jacquinot's specimen, but Jacquinot's figures of it, adding the 

 information that it was takeu under stones at low-tide on the 

 coasts of the Auckland Islands, and proposing to make it the type 

 of a new genus Hombronia, most likely in total ignorance of White's 

 Halicarcinus. In 1885 Eilhol states that Halicarcinus planatus 

 has been recorded from the Auckland Isles by Hombron and 

 Jacquinot, and then proceeds to establish as a separate species 

 Halicarcinus tridentatus (Jacquinot & Lucas), of which he gives a 

 figure (pi. 50. fig. 3), having found the species, he says, in Cook's 

 Sti'aits. To the work in which Hombron and Jacquinot record 

 H. planatus he gives no clue. He does not refer in his text to his 

 figure of H. tridentatus, which has a much less comparative width 

 of carapace and much more slender chelipeds than the figure on 

 Jacquinot's plate. He speaks of the description of this species 

 given by Jacquinot and Lucas as being incomplete, which it might 

 well be, since Jacquinot did not describe it at all, and Lucas only 

 described what Jacquinot figured. It is difficult to tell whether 

 Lucas is quite serious about some of the details, but he had no 

 specimen by which to control the drawings. M. Filhoi tells us 

 that the maxillipeds present very slight differences from those of 

 H. planatus, but what those differences are he neither says nor 

 shows, though Jacquinot's figure, with the last joint attached in 

 the middle of the penultimate, absolutely excludes Halicarcinus. 

 That the carapace is without lateral teeth M. Filhoi does mention, 

 and this may well be in agreement with Jacquinot's species, but it 

 is contrary to the character of Halicarcinus given by White. 



White's other synonym, Hymenosoma leachii Guerin, is not wholly 

 free from difficulty, for though Daua, Miers, and Haswell accept 

 it as identical with A. planatus, Milne-Edwards (1853) upholds it 

 as an independent species, and Miers in 1886 regards Halicarcinus 

 ovatus 8timpsou as rlie representative on the Australian coast of 



