662 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the last case, a mesodermic proliferation at the free margin of the fin 
appears to be originated from the ectoderm, the scleroblasts of the rays 
are ectodermic to begin with, and a germinal zone at the margin con- 
tinues to furnish fresh material as growth goes on. He finds further 
corroboration in a study of Teleosteans, and extends his conclusions 
tentatively to higher Vertebrates. At the end of his paper there is an 
interesting speculative suggestion as to the possible connection between 
skeleton-making and epidermic excretion, but these and other specula- 
tions are perhaps of less importance than his definite facts, showing in 
certain cases the ectodermic origin of scleroblasts for which the meso- 
derm previously got credit. Here we have another corroboration of 
Kleinenberg’s words, “ There is no mesoderm.” 
Phytogeny of the Tongue.* — - Prof. C. Gegenbaur begins an 
interesting essay on the tongue with a brief sketch of the numerous 
modifications which this organ exhibits in the Vertebrate series. In 
Pishes it is a fold of mucous membrane covering part of the hyoid, with 
no mobility except what it owes to the hyoid, and with considerable 
monotony of structure. It includes mucous membrane (it may be with 
hard teeth), a skeletal support, fat and connective tissue. It is with 
Amj)hibians that the mobile muscular tongue begins, which has proved 
itself so useful an organ. But how came it to be muscular? “Das 
Erreichte kann nicht als Ursache gelten.” 
The author describes what he has observed as to the development of 
the tongue in newt and salamander, how a small protrusion of mucous 
membrane occurs in front of the hyoid, how this exhibits connective- 
tissue proliferation, how it becomes in part a sensory but yet more 
a glandular organ, and how finally, during metamorphosis, muscular 
strands from the sterno-hyoid and genio-hyoid enter into its compo- 
sition. 
The tongue is first then a glandular organ, a function fully justified 
in the Amphibian’s later life, and the original import of the musculature 
was probably in connection with the glands. Thus the missing link in 
the evolution of the tongue is plain, the musculature was from the first 
of use to compress the glands. The dwindling of the glandular function, 
the increase of musculature, the taking on of new functions, the modifi- 
cations of detail, present no special difficulty. It is thus that ontogeny 
helps out phylogeny. 
Development of Venous System of Mammals. f — Prof. F. Hochstetter 
has followed up his previous researches by a study of the venous system 
in embryos of rabbit, cat, man, &c. He first discusses the venous 
system of the liver and then the modifications of the posterior cardinals 
and the development of the postcaval. After a comparative survey of 
mammals, he notes a series of important variations which occur. His 
paper is necessarily very complex, and we must restrict ourselves to 
one section of it. 
Of the right posterior cardinal the proximal portion remains, from 
its opening into the ductus Cuvieri (later V. cava superior sinistra) to 
the eighth thoracic segment, as the main stem of the V. azygos. From 
* Morphol. Jahrb., xxi. (1894) pp. 1-18 (5 figs.). 
t Op. cit., xx. (1893) pp. 543-648 (3 pis., 16 figs.). 
