| (106) | (1743) | (3056)
| | | (0.18) | | | |
| | | | | | |
H. s. altae | 7 | 2-22| 0.14- |110-130| 104-117 |1853-2106|3379-4056
| | (11)| 0.18 | (120) | (112) | (2008) | (3775)
| | | (0.15) | | | |

_Cranial Osteology._--The skull of _Hyla boulengeri_ is as long as it
is wide, and is flat; the premaxillary is small and bears 13 to 17
teeth (mean for 6 specimens, 14.9). The alary processes of the
premaxillaries are widely separated, concave posteriorly, and vertical.
Ventrally, the premaxillary is connected to the prevomer by bony
tissues. The maxillary is slender and bears 70 to 91 teeth (mean for 6
specimens 78.1). The pars facialis of the maxillary is laterally convex
and about four times as high as the pars dentalis.

The nasal is large (its length about 40 per cent of total length of
skull), and pointed anteriorly and posteriorly in dorsal view. The
nasals are separated anteromedially by the cartilaginous septum nasi.
One or two protuberances are present on the midlateral concavity of the
nasal. Posteriorly, the nasal overlaps the sphenethmoid and articulates
with the palatine. Dorsally the sphenethmoid is large, pentagonal, and
completely ossified. The frontoparietal is elongate, smooth, and bears
a small supraorbital process on the anterior edge of the orbit. A
keyhole-shaped frontoparietal fontanelle is present; the fontanelle is
narrow anteriorly and wide posteriorly.

The bony part of the prooetic is separated dorsally from the squamosal
by the cartilaginous crista parotica. The squamosal is small, its
anterior arm slender and pointed. The posterior arm of the squamosal is
pointed terminally and articulates with the prooetic medially.

The prevomer is large and elongate. Anteriorly the prevomer is
connected to the maxillary-premaxillary articulation; posteriorly, the
prevomer is separated from the sphenethmoid by cartilage. Each prevomer
bears six to nine teeth. The palatine is present and edentate. The
anterior end of the parasphenoid is broad (less pointed than in _Hyla
foliamorta_). The pterygoid is slender and well developed.

_Natural History._--_Hyla boulengeri_ inhabits humid lowland tropical
forests and breeds in temporary ponds. Clasping pairs and gravid
females were observed at Puerto Viejo, Heredia Province, Costa Rica