390 
E. RAY LANKESTER. 
corresponding to the splitting which forms the lymph-space of 
the metapleura. The artifact canals which have been mistaken 
for natural ventral canals (Bauchcanale) lie in one of two 
situations either of which is impossible for a natural lvmph- 
space, viz. between the connective tissue and the epidermis or 
between the connective tissue and the muscular fibres. 
The Lymph Spaces of the Dorsal and Ventral Fin-Rays. — 
I have already spoken of these above in treating of the fin- 
rays. Hatschek ( f Anatom. Anzeiger,’ August 15th, 1888), 
has shown that they are originally in continuity with the myo- 
coelomic pouches (see Plate XXXVI A, figs. 6 and 7). 
Rolph, Langerhans, and Schneider have recognised and 
described the character of the “ fin-ray boxes” or lymph- 
space compartments and their epithelial lining. Fine canals 
passing from these spaces have been described and are 
noted by Schneider. Such fine spaces and irregular canals 
are to be seen in the thick connective tissue which forms the 
substance of the fin-membrane (as distinguished from the 
fin-rays) of the caudal fin and praeoral lobe. Schneider states 
that he has not seen a coagulum in the “ fin-ray boxes,” but 
such a coagulum occurs not unfrequently. 
The Intra-notochordal Lymph Canals. — In sections of Am- 
phioxus may be observed dorsally and ventrally within the 
notochordal sheath a clear space, the natural shape and extent 
of which appears to be that given in PI. XXXVI. The dense 
laminar structure of the notochord is here deficient and replaced 
by short intercrossing fibres. Adequate staining with hsema- 
toxvlin reveals a number of small nuclei in the neighbourhood 
of these spaces in connection with the fibres. Other nuclei 
are seen in a series on either side in the lower half of the 
notochord, bnt nuclei do not occur deeply nor generally within 
the notochord (see PI. XXXVI A, fig. 1). The dorsal and 
ventral space thus seen in sections are due to the existence 
of a dorsal and ventral lymph-holding space which have not 
sharply defined walls, but are bounded by loose fibres. The 
more dorsal of these canals was first observed by Kossmann 
(14), and the somewhat smaller ventral one by Camille Moreaq 
