The swell shark, Cephaloscyllium ventriosum Garman (Scyliorhinidae), is an inshore, reef-dwelling, nocturnal species of the Eastern Pacific rim. Reproduction is oviparous. One ovary is developed. Ova are transported through the coelom by cilia, to a single ostium, which serves both oviducts. Egg formation is usually synchronous in both oviducts, and proceeds generally as in other elasmobranchs, but published and new data are combined in a new description of the egg-forming sequence. Photomicrographs show sperm stored in the shell-secreting tubules of the shell gland. This storage allows the production of fertile eggs in the absence of males for some months after mating.
A membrane surrounds the embryo and yolk during the early stages of development, contrary to prior descriptions of related species. A chalaza-like structure is attached to this membrane.
The young of this and several other oviparous species of sharks possess two dorso-lateral rows of enlarged denticles. In the swell shark, these appear to function in the emergence of the shark from the egg-case.
Eggs are preyed upon in nature, possibly by a Stenoglossid gastropod.
The sharks form at least two different populations, separated by as little as 30 km. The egg-cases of one population have no tendrils over 2cm.; the other population has long tendrils, to 2 m. Differences are also found in egg size and in the morphometrics
of the adult sharks. / Science, Faculty of / Zoology, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/34752 |
| Date | January 1970 |
| Creators | Grover, Charles Allan |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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