152 Miscellaneous. 



which have become smaller when transported from a comparatively 

 thin liquid into a denser one. 



It is well known, however, that E. H. Weber long since ascer- 

 tained, in the mesentery of living frogs, the presence of lymphatics 

 surrounding the capillary blood-vessels. Under the microscope he 

 saw the rapid currents of the blood surrounded on all sides by the 

 current of the lymph, which was from ten to twenty times as slow, 

 these currents being separated from each other by the arterial coat 

 in such a manner that there was no mixture of the globules of the 

 lymph with those of the blood. 



As I have neither time nor space for the exposition of the histo- 

 rical investigations which I have made upon this subject, they will 

 find a place in the fourth volume of the * Journal d' Anatomic et de 

 Physiologic,' where this memoir will be published entire. 



To sum up. From the numerous observations and experiments 

 which I have made, it consequently follows that the cutaneous and 

 subcutaneous vessels described by Monro, Hewson, &c. as lympha- 

 tics are veins; some in the condition of true veins, others in that of 

 venous sinuses. Beyond these veins it is impossible to inject any 

 vessel, either by means of mercury or otherwise. The division of 

 the lymphatics of fishes into superficial and deep-seated or visceral, 

 still adopted by some modern authors, must, consequently, l)e aban- 

 doned, the former kind of vessels not existing in this class of Ver- 

 tebrata. — Comptes Rendus, January 7, 1866, pp. 20-24. 



On Xenacanthus Dechenii. By Prof. Kner. 



Professor Kner has investigated the fossils referred to Xenacanthus 

 Dechenii (Bejv.) in the Museums at Vienna, Dresden, Berlin, and 

 Breslau, and states the results of his examination as follows : — 



1. From the structure of its fins, it cannot be approximated either 

 to Squatina or to any other genus of Plagiostomi or Cartilaginous 

 Fishes ; nor, notwithstanding its peculiarly formed and frequently 

 united ventral fins, can it be placed in the vicinity of the Discoboli. 

 It rather represents a genus singularly intermediate between the 

 Placoids (Selachii) and Malacopterygii, one of the transitional forms 

 characterized by Agassiz as "prophetic types," and, in Professor 

 Kner's opinion, can only find its nearest allies among living fishes 

 in the great group of the Siluroidei, although still very distant from 

 these. 



2. It is certain that Diplodus (Agass.), Orthacanthus (Goldf.), 

 and Xenacanthus (Beyr.) are generically identical ; and this state- 

 ment probably applies also to Pleuracanthus (Agass.). 



3. On the other hand, however, it seems very probable that 

 Xenacanthus Dechenii will have to be divided into at least two spe- 

 cies, which might be characterized as Icevidens and ptijchodus, unless 

 the remarkable differences are merely sexual. — Bericht der Akad. 

 d. Wiss. in Wien, January 3, 1867, p. 6. 



