Zoology Answers

In stumbled upon the following sentence in Chordate Embryology and Histology while reading a paragraph on the Fate map of amphibian blastula-

Beneath the notochordal mesoderm and towards the vegetal pole there lies a narrow strip of cells which forms the prechordal connective tissues of the embryo and hence the strip is called pre-chordal plate.

Here's a link to an image which I wish to attach with this question: http://biology.stackexchange.com/questions/53457/pre-chordal-plate

What are prechordal connective tissues that this prechordal plate forms later in development?

I have been reading Classification of Pisces by Romer 1966 and stumbled upon these two characters:
Members of series Pisces have paired and unpaired fins supported by SOFT or spiny fin rays.
Soft fin rays are fin rays that are flexible, non-rigid, SEGMENTED and sometimes branched.

While again as a character of Actinopterygii subclass the book mentioned that they have fins supported by ''JOINTED radiating rays''.

What does Jointed radiating rays mean? Does it mean that members of actinoptrygii have only soft fin rays?

P.S. I'm confused.Explain in a very simple manner, if you please.

What is meant by soft and spiny rays?

Is it related to the tissues the fin rays are made up of? The soft's got no bone/cartilage and the spiny's got bone/cartilage?

A read the following in a Zoology practical book. It was about Actinopterygii -

Basal support of paired fins project beyond the body wall.

What does it mean? Is it true for Subclass Actinopterygii?