Hi Sarah!
Please have a look at these picts to see if they are similar to the one you have:
http://images.google.it/images?hl=it&q="saddle connection"&u...

Here there is an explanation of what a "saddle connection" is and it's taken from a UK site (http://draindomain.com/pipe bends and junctions.html):
Saddle Connections
Saddles or junction blocks were until fairly recently commonly used for making a new connection onto an existing drain or sewer, this involved cutting a hole in the host pipe and fitting the saddle onto the pipe, there were usually two ways of going about this operation.

A template of the saddle connection was made and transferred onto the host pipe, the hole required was then carefully cut using either stitch drilling or the use of a small diameter grinder with the saddle then being adhered to the host pipe using concrete with the internal wall of the host pipe being made good with fast setting mortar or similar.



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Note added at 5 giorni (2009-02-25 10:40:07 GMT) Post-grading
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Grazie a te, Sarah!