422 
PROFESSOR POUCHET. 
P. Langerhans, in 1873^ mentions^ the same cells; ne 
describes them as very much branched (reich verastelt), and 
compares them, as doesO\vsjannikow,tothe cells of the cornea, 
and corroborates the description of Stieda, although this is 
limited to the quotation from Reichert, which rather goes 
against the existence of such cells. 
Quite recently Ant. Schneider^ admits the truth of 
Reichert’s ideas, and at the same time describes (pp. 1 and 
28) and figures in the laminar tissue of Amphioxus stel- 
late fibro-plastic cells, inserted by their prolongations on 
the walls of the true capillaries around the mouth. 
These quotations suffice to show the confusion and incom- 
pleteness of our knowledgeof the laminar tissue of Amphioxus, 
and of the farmed elements which it presents. As we shall pre- 
sently show, even if it is possible to find isolated cells having 
the ordinary appearance of stellate fibro-plastic cells, it is 
quite exceptional at least in the adult. In our preparations we 
have found one or two in the thinnest region of the caudal 
lophioderm, quite at the extremity ; with this exception we 
have not come across them. It is in fact a very decided 
character of the laminar tissue of Amphioxus that the formed 
elements analogous to the fibro-pjastic cells never appear 
in an isolated state, and that they are always united again 
into scattered groups or in longer or shorter rows which 
are more or less regular, and anastomose to a greater or 
less extent, forming cords which are sometimes solid iund 
sometimes hollow for a certain distance, or even form large 
spaces. 
It is these cords, which are partly solid, partly hollowed, 
and generally slightly elongated, which have been described 
as ^'systems of canals.” The supposed branched cells of 
Owsjannikow are only the enlargements of this very irre- 
gular network in the neighbourhood of the mouth. 
II. As these cordons and spaces formed by the coalescence 
of the cells of the connective tissue are situated to a large 
extent in the layer of laminar tissue which surrounds the 
body of the animal, we shall first of all describe this,^ add- 
ing, however, but little to the descriptions of Stieda. 
Below the epidermis you get, passing from without in- 
wards — 
^ “Zur Anatomie des Amphioxus lanceolatus,” in *Arch. f. Mik. 
Anat.,’ 1873, p. 301. 
2 ‘ Beitriige zur vergleichenden Anatomie,’ 4to, Berlin, 1879. 
3 Compare with this the strueture of the skin in fishes. See Pouchet, 
“Du developpement des poissons osseux,” ‘Journal de 1’ Anatomie,’ May- 
June, 1879, pp. 288-289. 
