552 Prof. W. X. Parker. On tJie Anatomy and [May 28, 



yellowish granules. Gradations between these and rounded cells of a 

 deeper yellow or brown colour can apparently be made out; the latter 

 arc arranged in larger or smaller groups, and cells appearing to be 

 intermediate forms between these and the ordinary black branched 

 pigment cells can also be seen. The lymphoid tissue is penetrated 

 by networks of blood-vessels, and it seems probable that the yellow 

 grannies mentioned above are due to the disintegration of red 

 corpuscles, which are ingested by leucocytes, and then undergo some 

 change, whereby the latter gradually pass into the condition of black 

 pigment cells, which migrate through the epithelium, and are so got 

 rid of. The muscular layers are very thin. A muscularis mucosee is 

 present, and the circular and longitudinal layers are represented, but 

 the direction of the fibres is in many regions difficult to trace. 

 Strands, only a few cells in thickness, extend throughout the 

 lymphoid tissue of the intestine, and some of these unite to form a 

 longitudinal band passing down the axis of the spiral valve. 



An analysis of the contents of the gut, for which the author is 

 indebted to Professor Baumann, while yielding negative results as 

 regards the stomach, proves the presence of peptones, in small 

 quantities, in the intestine. The question as to the mode of digestion 

 and absorption of the food in Protopterus is discussed. 



The branchial apparatus shows signs of considerable reduction. 

 Internal gills are present on the posterior face of the hyoid, on both 

 faces of the third and fourth branchial arches, and on the anterior 

 face of the fifth. Three pairs of external gills were present in all 

 specimens, even the largest, examined. The pulmonary apparatus, on 

 the whole, more nearly resembles the air-bladder and its duct of certain 

 Ganoids than the lungs and laryngo-tracheal chamber of Amphibians. 

 The pulmonary branches of the vagus cross one another at the base of 

 the lungs. 



The blood is remarkable for the large size of its elements, which 

 is only exceeded in the case of Proteus and Siren, as well as for the 

 large proportion of white corpuscles in comparison with the red ones. 

 Two forms of the former are described, in one of which fine radiating 

 pseudopodia can be protruded, and different stages in the degenera- 

 tion of the nucleus and cell-body could be observed. The chief points 

 of interest with regard to the blood-vessels are as follows : (1) the 

 presence of a paired pulmonary artery, the left supplying the ventral, 

 and the right the dorsal, aspect of the lungs ; (2) the presence of a 

 single true post-caval, along with a persistent left posterior cardinal 

 vein ; and (3) the single caudal vein, giving rise to a right and a left 

 renal portal. 



No external sexual differences could be observed, and amongst the 

 specimens examined, females were the more abundant. The urino- 

 genital organs are surrounded by masses of tissue resembling the 



