Why does parse-row work but add-bates-number not?

gistfile1.clj

(defn parse-row
  "Parse a row of text applying the headers in a keyword map"
  [headers & opts]
  (let [p #(parse %1 opts)]
    (comp (partial zipmap headers) first p)))

(defn add-bates-number
  "Add the bates-number key (and value) to the collection"
  [h id-ord]
  (comp #(conj {:bates-number (get %1 (keyword (nth h id-ord)))} %1)))

(defn parse-lines
  "Parse the specified sequence of lines using the row as a header which will
   be applied to the rest of the sequence returning maps.
   The text qualifier and delimiter characters will be automatically determined"
  ([lines]
     (parse-lines lines 0))
  ([lines id-ord]
      (let [hrow (first lines)
            qualifier (get-qualifier hrow)
            delimiter (get-delimiter qualifier hrow)
            h (parse-header hrow :delimiter delimiter :quote-char qualifier)]
        (map (#(add-bates-number %1) h id-ord)
              (lazy-seq
               (map (#(parse-row %1 :delimiter delimiter :quote-char qualifier) h)
                    (rest lines)))))))