This is unpaired and is bounded by the premaxillae (fig. 43, A, 8).
Hyla robertmertensi has a reverse of this pattern in that the primary note is paired and the secondaries are unpaired.
It may be noted as a peculiarity of the mandibular arch that it is never provided with an unpaired basal element.
As pointed out by Mivart, a longitudinal bar is also occasionally formed to support the cartilaginous rays of unpaired fins.
It constitutes in front an unpaired trunk, at first very small, opening into the right allantoic vein, close to the heart.
The left of the two eventually atrophies, so that there is formed an unpaired allantoic vein.
The fins are divisible into two main categories—the median or unpaired fins and the paired fins.
The labium is not developed from a pair of tubercles, as is usual, but at once appears as an unpaired, or single organ.
Transcriber's Note: Obvious punctuation errors, such as missing periods or unpaired quotation marks, have been corrected.
These were largely marbled ducks, all unpaired; but there were also very large aggregations of mallards.