INDUSTRIAL PROGRESS DURING THE YEAR 1871. cxlv 



fessor Orton in his second journey across the Ancles and 

 down the Amazon. They belong to fresh-water genera, and 

 help to define the nature of the habitat of the group. They 

 confirm the opinion of Mr. Conrad, previously expressed, that 

 the deposit was a basin of fresh water, to which brackish 

 water had access at times. The Hemisinus is a melania-like 

 shell, which occurred crowded in the clay in such perfection 

 that the species must have lived and died on the spot, and 

 as the living shells of the genus inhabit the fresh-water rivers 

 of South America, very far from salt water, they are as much 

 fresh -water as are those of Melania. The Pebas clay is 

 crowded with other fresh-water shells of the family of Me- 

 laniidce. 



Professor Verrill skives an account of the oio- a ntic cuttle- 

 fishes of Newfoundland, illustrating his remarks by some 

 facts heretofore unknown regarding the smaller New En- 

 gland forms. Meanwhile a gigantic cuttle-fish, measuring 

 about fourteen feet long, has been captured in Japan. 



Dr. Stieda has published a memoir on the nervous system 

 of the Cephalopods. 



The Ammonites have been studied by Professor Hyatt in 

 an original way. He finds that the gaps between forms or 

 species may be largely explained by the later mode of devel- 

 opment if the necessary care is taken to study the earlier 

 stages, which should show the close genetic connection of 

 the distinct adult forms, and explain thereby the absence of 

 the intermediate varieties. For example, by carefully ob- 

 serving these principles it is possible to trace the entire fam- 

 ily of Arietidce to one original variety of one species the 

 smooth variety of Psiloceras 2)lcmorbis. He finds that a se- 

 ries of species has, like an individual, a certain store of vital 

 power, which enables it for certain periods, more or less pro- 

 longed, to evolve new forms and new characteristics, but 

 which in the end fails ; and in place of further progress in 

 that direction we find an evolution of degraded forms, which 

 compare exactly with the retrograde metamorphoses of the 

 individual. 



M. Perez has published some researches on the mode of fe- 

 cundation of the eggs in gasteropod mollusks, particularly 

 the land-snails, while M. Dubrueil has finally completed his 

 physiological studies on the genital apparatus of Helix. 



