362 BULLETIN OF THE 



Okder AMPHIPODA. 



Family ORCHESTID^E. 

 Genus ALLORCHESTES. 



Syn. 1849. Allorchestes (in part) Dana, Amer. Jour. Sci. [2], VIII. 136. 



1852. AllorcJiestes (in part) Dana, Proc. Amer. Acad. Sci. Boston, II. 205. 

 1852. Allorchestes (in part) Dana, U. S. Explor. Exped. XIII, Crust. Pt. 

 II. 8S3. 



1856. Allorchestes Bate, Rep. Brit. Assoc. 1855, p. 57 (no descrip.). 



1857. AllorcJiestes Bate, Ann. Mag. Nat. Hist. [2], XIX. 136. 



1861. Allorchestes Bate and Westwood, Brit. Sessile-eyed Crust. I. 38. 



1862. AllorcJiestes Bate, Cat. Amphip. Crust. Brit. Mus. p. 34. 



1866. AllorcJiestes Heller, Beitr. z. nah. Kennt. d. Amphip. d. adriat. 



Meeres, p. 4. Denkschr. d. Math.-Natur. Classe d. Akad. d. 



"Wissensch. 

 1874. Hyalclla Smith, Rep. U. S. Fish Comm. for 1872 and 1873, p. 645. 

 1874. Hyalella Smith, Rep. U. S. Geolog. Geograph. Survey of Colorado 



for 1873, p. 608. 



First maxillas with small uniarticulate palpi. Palpus of the maxillipeds 

 composed of four segments, the distal segment usually bearing a movable 

 spine at its apex. First antennae shorter than the second antennas, longer 

 than the peduncle of the second antennas. First and second thoracic legs 

 subcheliform. Propodite of second pair larger than propodite of first 

 pair, and much larger in the male than in the female. Telson short and 

 entire. 



• Differs from Nicea Nicolet (as limited by Bate and Heller) in having the 

 telson single instead of double or cleft. The fourth segment of the palpus 

 of the maxillipeds is well developed, as in Nicea and (Jammarus, and, as in 

 these genera, is commonly unguiculiferous. Neither Dana, in describing 

 AllorcJiestes, nor Nicolet, in his description of Nicea * (published in the same 

 year), mentioned the form of the telson. The two names were therefore 

 synonymes. Bate, in a list of British AmpJiipoda, published in 1856 in the 

 Report of the British Association for the Advancement of Science, indicates, 

 without describing, two genera, Allorchestes Dana and GalantJiis, gen. nov., 

 which, as appears from his subsequent descriptions, were based upon the 

 trivial character of a different relative length of the first and second an- 

 tennas, and a differently formed telson; Dana's name, Allorchestes,' being 

 restricted to those species in which the first antennas are (at least) as long 



* Gay's Historla de Chile. Zoo!., III. 237, 1849. 



