The rhyme pattern here, in my view, doesn't correspond to anything especially meaningful or recognizable in the established poetic forms of literary history. We see the following scheme for the opening stanza:
In spite of a slight irregularity, however, one could judge it to contain two six-line sub-stanzas with an extra rhyme added between the fourth and "fifth" lines of the second sub-stanza, the extra line being the third "E" rhyme. But even if we disregard this additional line, the two sub-stanzas still don't show the identical rhyming pattern.
Obviously Eliot intended this irregularity. As in "Prufrock," the rhymes seem randomly placed. Ever since Whitman and his use of free verse, poets saw no absolute need to employ rhyme or meter. Neither Eliot's "Prufrock" nor his "Preludes" are written in free verse per se, but they nevertheless don't follow the specific patterns we associate with verse from the periods before Whitman and modernism.
The irregularity is probably meant...
(The entire section contains 4 answers and 916 words.)