QUEEN CHARLOTTE ISLANDS. 209 B 



Oregonia gracilis Dana. 



Oregonia gracilis Dana, United States Exploring Expedition, Crust., p. 106, 

 pi. 3, fig. 2, 1852(f). 



Oregonia hirla Dana, ibid., p. 107, pi. 3, fig. 3, 1852 ( ? ). 

 ? Oregonia longimana Bate, Proceedings Zoological Society London, 1864, p. 

 663, 1865 ; in J. K. Lord, Naturalist in Vancouver Island, ii., p. 

 267, 1866. 



Virago Sound, Q.C.I., 15 to 8 fath., also Vancouver Island. 



The series of specimens is sufficient to show that the two forms 

 described by Dana are sexual and belong to one species, the gracilis 

 being based on the adult male and the hirta on the two forms of the 

 female. In the characters of the rostral spines and the rest of the 

 carapax, all the larger males before me agree with the description and 

 figures of gracilis, while in tbe same characters the females agree with 

 hirta, and the smaller males are more or less intermediate between the 

 two forms. But among the females themselves there are two forms : 

 all the adult and fertile specimens having the abdomen very broad and 

 nearly orbicular, while in other specimens (most of them small, but 

 some of them as large as the smaller of those with orbicular abdomens) 

 the abdomen is much narrower and elliptical, as shown in Dana's fig. 3 

 b. The smaller of these latter females are, perhaps, merely immature 

 individuals, but the larger are apparently truly dimorphic, sterile 

 females, such as are found in many genera of Brachyura, and here, as 

 in most similar cases, the larger of the sterile individuals show consid- 

 erable approach to the male in the form of the carapax, etc. 



In the largest male before me the merus of the chelipeds reaches 

 very nearly or quite to the tips of the rostrum, and, in this respect, 

 agrees with Bate's 0. longimana, though the chelipeds are not nearly 

 twice as long as the carapax, if the rostrum is, as it is usually, included 

 in the length. Bate makes no allusion to the size of his specimen, and 

 describes it so imperfectly that it is not easy to determine its affinities 

 with certainty.* 



* It may be well to remark here that there had apparently been an admixture of specimens 

 from some region or regions far south of Vancouver Island, in the collection which served as 

 the basis of Bate's chapter on " Vancouver Island Crabs " in the work above referred to, and 

 that this fact also adds to the difficulty of determining the species there described. Bate him- 

 self remarked upon the mingling of northern and southern forms in the collection, but he does 

 not seem to have suspected any mistake in regard to the localities from which the specimens 

 came. I am aware that many tropical and subtropical marine species extend far north along 

 the Pacific American coast, but it is scarcely conceivable that such an assemblage of species as 

 Bate's list indicates should exist in any one fauna! region. The list contains not only tropical 

 Pacific American species but also Central and South Pacific, and even tropical Atlantic species. 

 Some of the incongruities may, however, be due to wrong identifications, as in the ease of the 

 Cllbanariiw about to be mentioned ; but, making all reasonably supposable allowance for mis- 

 takes of this kind, there is still sufficient evidence of a mixture of specimens from different fauna?, 

 to throw doubt upon the authenticity of the supposed habitats of many of the new species in 

 Mr. Lord's collection. The existence in the region of Vancouver Island of any of the following 

 species (all of which are enumerated among the Decapoda in Bate's list) is, at least, very doubt- 

 ful :—Eriphia gonagra, " Pcmopceus" crenatiis, Xantho dispar, Ocypode VvvuHi, Grapsits liridus, 

 Hemigrapsus " sedentatvs," Gelasimus annulipes, Porcellmia Edwardsii, Eupagurus perlatus, 



