116 Dr. R. H. Traquair on the Anatomy of Calamoichthys. 



arteriosus, which is furnished internally with numerous valves, of 

 unequal size. The branchial artery gives oflf first a large lateral 

 branch on each side, which divides into three for the three pos- 

 terior gills ; the trunk then bifurcates, giving off a branch for 

 the anterior gill of each side. As in Poli/pterus, the posterior 

 gill has only one row of leaflets, and the cleft behind it is want- 

 ing. No trace of a " pseudobranchia " was found, an organ 

 likewise absent in Polypterus. The spleen is very long and 

 slender, lying closely along the great air-bladder. The air- 

 bladders are two in number, opening by a common orifice into 

 the lower aspect of the throat, behind the gill-clefts. That of 

 the left side is small, being only 2f inches in length in a fish 

 of 10 inches ; it is closely adherent to the side of the oesophagus 

 and commencement of the stomach. That of the other side 

 measures 8f inches in the same fish, and extends through the 

 whole length of the abdominal cavity, lying closely along the 

 under surface of the vertebral column. 



Like the rest of the abdominal organs in general, the kidneys 

 are very slender and elongated ; each consists of a number of little 

 lobules, which lie in the concavities on the under surfaces of the 

 vertebral bodies. The excretory duct or ureter lies along the 

 outer border of the organ, and passes straight backwards to 

 unite with the genital duct, and, with its fellow of the opposite 

 side, at the urogenital pore. The ovaries and oviducts corre- 

 spond exactly with Miiller's description of these organs in Po- 

 lypterus (Trans. Berlin Acad. 1844) . Each ovary is in the form 

 of a flattened plate, suspended in front of the posterior part of 

 the kidney by a mesentery, is solid, and consists of a stroma 

 imbedding ova of all sizes, up to -fV inch diameter. The ovi- 

 duct, proceeding forwards from the urogenital pore as a pretty 

 wide tube, crosses beneath the ovarian mesentery, and opens 

 into the peritoneal cavity, on the outer side of the gland, and 

 closely above its lower extremity. The ovaries are not sym- 

 metrical in position, one being in advance of the other, so that 

 also one oviduct is longer. In a female measuring 8f inches 

 the right ovary was 1^ inch in length, its anterior extremity 

 being placed 4| inches from the top of the snout, and the length 

 of the oviduct 1| inch, while the left measured If inch, was 

 situated at its anterior extremity 5f inches from the tip of the 

 snout, and had a duct of \-f-^ inch. The testes are very mi- 

 nute, and situated very far forwards, each being a small oval 

 body -j3g- inch in length in a male of 10 inches ; and in the same 

 specimen the right one was situated 2|, and the left 2^^ inches 

 back from the tip of the snout. A very minute duct runs back- 

 wards parallel with and close to the ureter, which it joins near 

 the urogenital pore. 



