Holt and Calderwood — Report on the Rarer Fishes. 461 



the outer surface, and resembles, therefore, the condition seen in many chest- 

 nuts which are on the one side convex, on the other flat. Both ovaries taken 

 together have about the capacity of a hen's egg. The ovarian wall is thick and 

 opaque, although near the commencement of the oviduct the pressure of the eggs 

 from within produces a somewhat granulated appearance. The eggs are small 

 and very numerous. After preservation in spirit they exhibit a yellowish red 

 colour. In the fresh condition they measured about 1"25 to 4-31 mm.,* and were 

 therefore not quite ripe, since CoUett found ova of 2 mm. in an example of this 



Owing to the swollen condition of the ovaries, the rectum has assumed a 

 much more horizontal inclination than is described in M. loevis and M. coelo- 

 rhynchus. The arrangement of the alimentary tract shows no peculiarity worthy 

 of note. 



The liver does not exhibit the one-sided condition seen in M. IcBvis. In the 

 species under consideration there are two large lobes, of equal size, lying side-by- 

 side in a similar manner to the condition already described in the case of the 

 ovaries. The lobes extend the entire length of the upper portion of the abdo- 

 minal cavity, curving over, and providing a large concavity for the superior 

 surfaces of the ovaries. The air-bladder is again somewhat peculiar. It is 

 almond-shaped, the narrow end being placed anteriorly. When a lateral opening 

 is made, it is seen to be roughly divided into an anterior, middle, and posterior 

 portions, and to be lined with a loose silvery-looking membrane which becomes 

 convoluted and spongy in the anterior portion. An imperfect septum divides the 

 middle from the posterior portion. The middle portion contains a complicated 

 mass of rete mirabile ; the anterior and posterior portions are simple and sac-like. 

 There is no pneumatic duct. 



The kidneys are so thin and insignificant above the bladder as almost to 

 escape detection. In front of the bladder, however, where the solid kidney 

 becomes divided, as in the other species of Macruri examined, the branches can be 

 followed into the region of the head, where they exhibit pronounced renal or 

 pronephric characteristics. This head-kidney has every appearance of being 

 perfectly functional. Numerous uriniferous tubules can readily be detected in 

 any section of it placed under the microscope, and a large ureter, which, on 

 opening the abdominal cavity, is readily seen passing downwards posterior to the 

 air-bladder, liver, and ovaries, can be traced forwards to this head-kidney. 



The presence of a head-kidney has been noticed in all the species of Macruridee 

 which have come under our notice. The appearance of functional activity given 

 by the presence of uriniferous tubules and a well-marked ureter is therefore of the 



* Vide Holt, stqira, vol. iv., p. 452, 



