172 DE. C. CHILTON ON THE SUBTEEEANEAN 



states of the same species^ and further he proposes to suppress the genus Nlphargus, as he considers it 

 only a modification of Gammarus pulex. To the single species Gammarus puteanus, Koch, he therefore 

 refers all the following forms : — I. Form : Gammarus minuhts, Gervais ; Crangonyx subterraneus, Spence 

 Bate. II. Form : Niphargus Kochianus, Spence Bate. III. Form : Gammarus puteanus, Caspary : 

 Gammarus puteanus, Hosius ; Niphargtis fontanus, Spence Bate. IV. Form : Gammarus puteanus, 

 Koch. V. Form : Niphargus stygius, Schiodte ; Gammarus puteanus, Koch, La Valette St. George, 

 and Plateau. VI. Form : a colossal specimen, 33 millim. long, from Neuchatel. 



These conclusions arrived at by de Rougemont have been very fully criticized by Alois Humbert [62, 

 pp. 294—296], Wrzesniowski [124, pp. 687-694], and others, who have shown that, in addition to the 

 inherent improbability of some of de Rougemont's assertions, there are so many inaccuracies, incon- 

 sistencies, and contradictions in his own work and such neglect to notice points of special importance, as, 

 for example, the difference between the undivided telson of Crangonyx and the deeply-cleft telson of 

 Niphargus, that de Rougemont's views cannot be seriously accepted. It is therefore unnecessary to 

 discuss the subject further, and I need only say that I feel quite convinced of the justice and truth of 

 the remarks made on the matter by Humbert and Wrzesniowski. It is of course quite possible that some 

 of the various subterranean species described under Niphargus {Gammarus) are not entitled to full specific 

 rank, but should rather be looked upon as local varieties, which, indeed, we might naturally expect to 

 arise owing to isolation ; but certainly we cannot admit that all the forms mentioned by de Rougemont 

 are modifications due to age, and if Crangonyx subterraneus, Spence Bate, can change at a single moult 

 into Niphargus Kochianus, Spence Bate, it will be useless to attempt to classify Amphipoda into genera 

 and species at all. The existence of five different forms in the single well at ^lunich, if this really was 

 the case, is not so strange or so unprecedented as de Rougemont seems to have thought it, for the space in 

 which they live is of course not merely the well itself, but the subterranean waters connected therewith, 

 which may be very extended ; and Spence Bate had pre\'iously recorded the three species Niphargus 

 fontanus, N. Kochianus, and Crangonyx subterraneus from the same well at Ringwood, England, while 

 Wrzesniowski has since recorded the two species Niphargus tafrensis and Boruta tenebrai-um living together 

 in one well ; and I have takeu from a single well at Eyreton the three Amphipods Calliopius subterraneus, 

 Gammarus fragilis, aud Crangonyx compactus, as well as the two Isopods Cruregens fontanus and 

 Phreatoicus typicus. 



A year later, in 1876, de Rougemont published a French translation of his paper on Gammarus 

 puteanus under the title " Etude de la Faune des eaus privees de la lumiere," and this contained in 

 addition a description of the Isopod Asellus Sieboldii, which Bovallius identified with the A. caraticus, 

 Schiodte, of earlier writers, though he retains de Rougemont's name, as he was the first to describe the 

 species [15, p. 11]. 



S. I. Smith, 1874, in a work on the Crustacea of the fresh waters of the United States [103], describes 

 both sexes of Crangonyx gracilis, Smith, an eyed species that has been already mentioned. He also 

 mentions Crangonyx vitreus, Packard, giving under protest Stygobromus vitreus. Cope, as a synonym ; 

 Packard, however, in his last work keeps the two separate [83, p. 34] . 



Smith also describes Crangonyx tenuis, n. s., " a slender, elongated species with very low epimera, 

 resembling more in form the species of Niphargus than the typical species of Crangonyx." 



In 1875, S. I. Smith [104], in a paper on the Crustaceans of the Caves of Kentucky and Indiana, 

 states that Crangonyx (Stygobromus) vitreus, Cope, is very different from Crangonyx vitreus, Packard, 

 of which he bad previously, as above stated, given it as a synonym under protest. The latter species is, he 

 says, closely allied to C. gracilis. Smith, from Michigan, Lake Superior, &c., differing principally in the 

 structure of the eyes. In his account of this paper, Stebbing adds, " Since Packard's species in any 

 case must yield its specific name, one is led by Professor Smith's account to regard it as a synonym of 

 Crangonyx gracilis " [108, p. 451], Packard afterwards refers to the species as C. Pachardii, Smith ; hut 

 I am unable to find when this name was assigned to it. 



