Marine Animal Forms in Fresh Water, 51 



fresh waters of Northern and Central Europe. That, on the 

 contrary, several species of Blennius occiu* in the fresh waters of 

 Southern Europe, has been already observed ; the family of the 

 Gobioidei includes numerous East Indian freshwater fishes, se- 

 veral belonging to the genus Gobius itself. As regards Pal^E- 

 mon, a freshwater crustacean (^ Camaron de agua dolce,' Palce- 

 mon Jamaicensis, A.) of Jamaica and Cuba has been known since 

 the time of Sloane and Parra ; and, according to an oral state- 

 ment of Dr.Engelmann,a species of this genus (still undescribed?) 

 lives near St. Louis in N. America. To the same family belong 

 the Sicilian Symethus fiuviatilis of Rafinesque, which, although 

 so imperfectly described and again denied, rests upon some 

 observation, and also the Hippolyte Desmarestii of Millet, dis- 

 covered some time since in the Mayenne, the Sarthe and other 

 rivers of the north-west of France * ; Dana^s Chilian freshwater 

 crustacean, CryjoAiojos spinulosomanus ; and lastly, the pale, eye-less 

 Cavern Shrimp [Troglocaris) of the Adelsberg caves. Associated 

 with the latter is the recently-discovered Monolistra; this has 

 hitherto been the sole known freshwater representative of the 

 Isopodes nageurs of Milne-Edwards [Cymothoidea, Dana), to which 

 Sphceroma belongs. 



Several families also, which, even in the region of the Mediter- 

 ranean as in the North Sea, are purely marine, — of which the most 

 remarkable examples are the Scomberoidea, and Sharks and Rays, 

 — are represented in tropical regions by freshwater forms [Mono- 

 cirrhus poly acanthus, Meckel, in the Rio Negro; Carcharias 

 gangeticuSj Miill. & Henle, sixty leagues above the sea; Pristis 

 Perrotetij Miill. & Henle, in the Senegal ; Raia fiuviatilis, Ham.- 

 Buch., near Kampur, 1000 English miles above the influence of 

 the tide; and the Trygon discovered by Schomburgk in the 

 River Magdalena). The entire section of the Brachyurous 



Fishes and Crustacea of the Italian Fresh Waters," the occurrence of a 

 Blenny in which was pointed out by Pollini as long ago as 1816. The 

 most important species observed by the author were — 



Atherina lacustris, Bonap. 



Blennius vulgaris, Pollini. 



Gobius jluviatilis, Bonelli. 



Leuciscus alburnellus, Filippi. 



Leuciscus Savignyi, Val. 



Alosa finta, Troschel. 



PalcBmon lacustris, n. sp., in the Lake of Albano. 



Sphceroma fossarum, n. sp., in the Pontine Marshes. 



These species are all described in the second part of his memoir, and both 

 this and the first part contain remarks upon other animals inhabiting the 

 fresh waters of the South of Europe, which belong to what ai'e generally 

 regarded as marine groups. — Transl.] 

 * Ann. Sci. Nat. xxv, pi. 10, fig. B. 1832. 



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