To help me understand what you're looking for, could you please provide more context or information? For example:
* Where did you encounter this term? (e.g., a book, website, lecture)
* What is the general topic? (e.g., biology, medicine, ecology)
* What do you think "biogaster" might refer to?
With more information, I might be able to figure out what you're asking about and provide a more accurate answer.