128 Chronicles of Science.” [Jan., 
organ of the ray and those of the other electric fishes gives a 
great importance to the study of that function in the ray, and this 
study should explain the peculiar electric phenomena discovered by 
M. Robin in the electric function of the ray, and which are not 
exemplified in the other electric fishes. 
Dr. Morch proposes a new classification of the Mollusca (‘Annals,’ 
December), inasmuch as he regards the organs employed in adopted 
classifications to have less systematic value than is usually attributed 
to them. The locomotive organs, on which were founded Cuvier’s 
primary divisions, Cephalopoda, Gasteropoda, &c., have been found 
by subsequent researches to have been somewhat misunderstood, at 
all events in their homological relations. Thus, Lovén and Huxley 
have shown that the Pteropods are true Gasteropods, and that the 
funnel of the Cephalopods is homologous with the foot of the Gymno- 
somata. The secondary divisions (or orders) of Cuvier were founded 
upon the respiratory organs, but special organs for this function are 
not always necessary. In Mollusca not requiring a hard covering 
for their protection, respiration takes place through the skin; but 
when the skin is thickened, or the shell developed, a respiratory 
organ becomes necessary. The larger the shell is in proportion to 
the uncovered parts of the animal, the more complicated and com- 
pressed are the gills. The insignificance of the gills as a systematic 
character is evident by comparing the Heteropoda, from the entirely 
gill-less Firoloids and Pterotrachza with external gills, to Atlanta 
exhibiting perfectly internal gills. The two kinds of respiratory 
organs indicate only relative superiority and inferiority, but not 
the limits of systematic division. Neither is the presence or absence 
of a head, though indicating relative superiority or inferiority, 
sufficient for natural divisions. Dr. Moérch, after twenty years’ 
study, is enabled to state that the heart and generative organs offer 
characters of a much higher systematic value than is generally 
believed, and the classification proposed by him is chiefly founded 
upon the male organ, which seems to him to be the best indicator 
of the sensibility of the nervous system, and consequently of the 
relative systematic rank of the animal. His synopsis confirms the 
rule of Professor Agassiz, that land animals are more perfect than 
marine ; but this rule may be explained in the sense that the divi- 
sions with the largest number of terrestrial forms always are the 
superior. The lowest class, Acephala, is entirely aquatic, and chiefly 
marine. There is also the same concordance with Professor Owen’s 
law, that the multiplicity of organs indicates inferiority in organi- 
zation. Thus the duplicity of the organs of Acephala descends as 
the system ascends. 
M. Paul Rocher, in a paper brought before the Academy of 
Sciences, makes some interesting observations upon the manner in 
