Shoshin Nagamine & Understanding Kata

In Shoshin Nagamine’s Essence of Okinawan Karatedo he states that the, “intermediate movements (fighting postures) are integrated into kata as links between paired units of basic movements.” The fighting postures that he lists include among others: ryu no shita no kamae (dragon-tongue posture), sagurite no kamae (searching-hand posture), suirakan no kamae (drunkard posture). What do these postures  mean and why did Nagamine list only a limited set of them?I cannot remember the term Nagamine uses exactly, but I think he refers to them as “positional coincidence” or something like that. Although these singular fighting postures have applications in and of themselves, they are also used to link series of techniques together into an integrated whole. Think of them as punctuation marks. You can’t write a sentence without punctuation. Why did Nagamine sensei only list those postures? I couldn’t say, but in terms of their meaning, if you understand the punctuation and know where the sentence begins and ends, then it makes it a lot easier to isolate sequences of techniques to use and study.