Contributions to the Study of the Morphology of Fish

Ballantyne, Frances M (1930) Contributions to the Study of the Morphology of Fish. DSc thesis, University of Glasgow.

Abstract

From the observations chronicled above it will be seen that Callichthys has several primitive features, while being in many ways a typical Teleost. The main points of interest in its development are: 1. The process of segmentation is similar to that of the egg of Salmo. 2. Development is very rapid and the embryo has many adult features by the time of hatching. 3. The chondrocranium is of the primitive platybasic type, and the trabeculae and parachordals are continuous. 4. The cartilaginous pectoral girdle closely resembles the visceral arches. 5. The anterior part of the vertebral column, with the air-sac capsule connected with it, is similar to that of other Siluridae, except that the first normal, probably the fifth, vertebra carries a large rib, comparable with the cranial rib of the Dipnoi. 6. The bony plates of the body, and probably some of the superficial bones of the skull, are of dermal origin. The bony plates have a row of denticles along their posterior border, similar to the denticles on the lepidotrichia of the paired and unpaired fins. 7. In the otocyst the two endolymphatic ducts meet in the middle line ventral to the brain, and send back a little diverticulum, the sinus endolymphaticus, which is embraced at the sides by the discs of the air-sacs. 8. The air-bladder is represented in the adult by a pair of air-sacs lying at either side in a bony capsule just behind the ear, with which they are connected by means of the Weberian apparatus. 9. The arrangement of the lateral line sense organs on the head is similar to that of the sense organs on the head of Osteolepis, one of the fossil Ganoids. 10. The gills are normal, but the fish also breathes by its membranous and vascular intestine. Probably the caudal and dorsal fins have a respiratory function as they are very vascular, especially during development. 11. The heart has a muscular conus. The last two afferents of each side come from the dorsal side of the ventral aorta as a single vessel, as they do in the Dipnoi. 12. The caudal vein continues forward as the inter-renal vein, which is again continuous with the right posterior cardinal. The left posterior cardinal is very short and in the adult has lost its connection with the inter-renal. There is a single inferior jugular vein, comparable with that of Polypterus, which opens into the right side of the atrium. 13. The development of the pectoral fins is somewhat similar to that of the pectoral fins of Polypterus, the fin having at first a solid axis with a fold of membrane around it. 14. There appears to be a persistent pronephros with a single very much enlarged glomerulus, right at the front of the opisthonephros in the middle line.

• Item Type: Thesis (DSc)
• Qualification Level: Doctoral
• Keywords: Zoology, Morphology
• Date of Award: 1930
• Depositing User: Enlighten Team
• Unique ID: glathesis:1930-79853
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 03 Mar 2020 10:31
• Last Modified: 03 Mar 2020 10:31
• URI: https://theses.gla.ac.uk/id/eprint/79853