What's an easy way to trim N lines from the tail of a file (without the use of 'head')?

Question

Say I've got a bunch of files that are all >100 lines long. I'd like to trim off the top 14 lines and the bottom 9 lines, leaving only the lines in the middle. This command will trim off the top fourteen:

cat myfile.txt | tail -n +15

Is there another command I can pipe through to trim off the bottom 9 without explicitly passing the length of the file?

Edited to add: My version of head (Mac OS 10.5) doesn't accept a negative number of lines as a parameter.