REPORT ON THE AMPHIPODA. 433 



1874. Smith, S. I. 



The Crustacea of the fresh waters of the United States, pp. 637-661. 

 Sketch of the Invertebrate Fauna of Lake Superior, pp. 690-706. Food of 

 fresh-water fishes, pp. 708-709. Extract from the report of Prof. S. F. Baird, 

 Commissioner of fish and fisheries, Part II, Pieport for 1 8 72-'73. Washington, 1874. 



At page 645, the account of the AmphiisoJa begins with the family ORCHESTiDiE, and the new 

 genus HiialeUa, thus described : — 



" First pair of maxilk* with rudimentary, very short, and uniarticulate palpi. Palpus of the 

 maxillipeds composed of five segments ; the terminal segment being slender and styliform, 

 and the penultimate broad. Antennula;, antennse, and thoracic legs much as in Hijalc. 

 Telson short, stout, and entire. 



" This genus seems to be closely allied to Hyale, but differs from it and from the rest of the 

 Orchestidx in the palpus of maxillipeds, which has five instead of four segments, showing 

 in this respect a remarkable approach toward the gammaroid group of Amphiiwda. From 

 Hyale it differs also in the telson." 



For a discussion of the genera Hyale and Hyalella, see Note on Rathke, 1837. Hyalella dentata, 

 n. s., pi. ii. figs. 8-10, is here described. After the description had been sent to the 

 printer, Professor Smith received many additional specimens from Lake Okeechobee, Florida. 

 In some of these, he says, " the dorsal teeth upon the first and second segments of the 

 abdomen are very small ; and, in a very few specimens, they are wholly, or almost wholly, 

 wanting." The Ariiphitlwr aztecus, Saussure, "undoubtedly belongs to this genus, and may 

 be called Hyalella azteca." Allorchestes kmclcei-boclieri of Bate " belongs probably to this 

 genus"; "the palpus of the first pair of maxillae, in Bate's species, is figured (perhaps 

 incorrectly) as composed of two segments." 



In the family Lysianassid^, " Pontoporeia Hoyi," pi. ii, fig. 5, is entered as a new species, with 

 the synonymy, " Ponioporeia affinis Smith, American .Journal of Science, 3d series, vol. ii, 

 p. 452, 1871 ; and Preliminary Report on Dredging in Lake Superior, p. 1022, 1871. 

 Gammarus Hoyi Stimpson, MSS., (full-grown male form.) Gammarus hrevlstylis Stimp- 

 son, MSS., (female) " Professor Smith had originally regarded his specimens " as specifically 

 identical with the Pontoporeia affiniis of the Scandinavian lakes and the Baltic. A subse- 

 quent and more minute comparison has, however, revealed some differences, which are 

 apparently constant." " The most remarkable differences are in the peculiar, elongated, 

 papilliform appendages upon the sternal portion of the thoracic segments." These, it 

 appears, are more numerous in the American specimens than in the European, as described 

 by G. O. Sars in 1867. A second new species, Pontojwreia filicornis {Gammai-us filicornig 

 Stimpson, MSS.), is founded on a single specimen. "This species differs remarkably from 

 all the heretofore known species of Ponfoporeina: in the excessive elongation of the flagella 

 of the antennul» and antennas, a character which might be regarded by some naturalists as 

 of generic value. The very close agreement with P. affinis and Hoyi in all other parts 

 of the animal, however, seems to indicate a very close affinity with those species, 

 especially the latter ; and as this one peculiarity is very likely only a sexual character of 

 the old males of the species, I retain the species in the genus." The detailed account seems 

 to make it doubtful whether the name Pontoporeia affinis would not suffice both for this 

 and the j)receding species. 



In the family Gammaeid^, is described Garniimrus limnxus, Smith, pi. ii, figs. 6, 7, (Gammarus 

 lacugtrit!, Smith, 1871), "this species is very closely allied to the Gammartif neylectus of 

 G. O. Sars, which inhabits the lakes of Norway," of which lacudris is a synonym, or 



(ZOOL. CHALL. EXP. — PART LXVII. — 18S7.) XxX 55 



