356 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
is effected only after the notochord-rudiment associated with the above- 
mentioned Scheitelrest has been differentiated, and is probably to be 
regarded as the reappearance of the cavity which originally traversed the 
Scheitelrest, 
Development of Excretory Organs in Bdellostoma.* * * § — Mr. G. C. 
Price was fortunate enough to secure a few embryos of Bdellostoma stouti 
Lockington. The “ mesonephros ” forms, as is known, the functional 
excretory organ of the adult, and has 26-81 tubules opening into the 
relatively large segmental duct ; the part called the jmonephros lies on 
each side in the pericardial cavity, but in the adult the lumen of its 
central duct has lost continuity with the lumen of the segmental duct. 
As in other Vertebrates, the rudiments of the pronephric segmental 
tubes grow into the rudiment of the segmental duct, and the lumen of 
the duct is formed in continuity with the lumina of the tubules ; in 
Bdellostoma , however, this is true not only of the pronephric part, but 
of the entire system, which is therefore primitive in a much more funda- 
mental sense than has hitherto been supposed. The author finds in the 
development and structure of Bdellostoma strong evidence in favour of 
Biickert’s theory that primitively the excretory system consisted of seg- 
mental tubules, w r hich opened independently of one another along the 
side of the body, and that the segmental duct has been formed from these 
tubules. 
Further Researches on Metamorphosis of Mursenoids.f — Prof. B. 
Grassi and Dr. S. Calandruccio are now able to say that they know the 
larval and semi-larval forms of all the Mediterranean Mursenoids ex- 
cept the very rare Cldopsis bicolor and the occasional Mursenesox savanna . 
They have followed the metamorphosis of Leptocephalus brevirosiris into 
adults, and note that the Leptocephalus stage of Myrus vulgaris is very 
like that of Ophichthys hispanus (syn. 0 . remicaudus), and that the “ Tiluri ” 
are probably referable to Serrivomer. 
Development of Eels.J — Prof. G. B. Grassi and Dr. S. Calandruccio 
have a note on two transitions between Leptoceplialus brevirostris and the 
young eel. The one had the dental teeth still intact; the other had 
lost them, but had not acquired the final set. 
Development of Hypochorda and Ligamentum longitudinale ven- 
trale in Teleostei.§ — Dr. K. Franz corroborates, in reference to trout 
and salmon, what other investigators have stated, that the hypochorda 
develops from the endoderm. It separates from a ridge springing from 
the dorsal wall of the gut. The separation is associated with the for- 
mation of segmentally arranged bridges, similar to those which Stolir 
has described in the frog. No lumen is ever demonstrable in the hypo- 
chorda. 
The ligamentum longitudinale ventrale arises from the cells of the 
axial mesoderm without the elements of the hypochorda taking any share 
in its formation. The hypochorda disappears (more rapidly in the 
salmon than in the trout) without contributing to any organ. 
* Zool. Jahrb. (Abtli. Anat.), x. (1897) pp. 205-26 (2 pis.), 
f Atti R. Acad. Lincei (Rend.), vi. (1897) p. 43. 
i Tom. cit., pp. 239-40 (2 figs.). 
§ Morph. Jalirb., xxv. (1897) pp. 143-55 (1 pi. and 2 figs.). 
