href="@public@vhost@g@gutenberg@html@files@31293@31293-h@31293-h-0.htm.html#fig1" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">Fig. 1) and less so in all other specimens examined. The illustration of the holotype suggests that it has equally prominent, but fewer, spinules (Gaige, 1926).

The holotype, a gravid female, is the largest known specimen (31 mm., snout-vent length). Another gravid female (AMNH 70108) has a snout-vent length of 26.2 mm.

Distribution.—All known specimens have been found in the foothills of the northeastern face of the Guiana Massif in British Guiana.

FAMILY POSITION

The following characters of Allophryne are those generally held to be useful in determining family relationships:

1. Presacral vertebrae procoelus, eight in number.
2. Parahyoid absent.
3. Free ribs lacking.
4. Bidder's organ absent.
5. Intercalary cartilages present in digits; phalangeal formulae 3-3-4-4 and 3-3-4-5-4.
6. Coccyx articulating with sacrum by two condyles.
7. Tarsal bones not fused.
8. Pectoral girdle arciferal.
9. Epicoracoidal horns present, free.
10. Terminal phalanges T-shaped.
11. Sacrum procoelus and diapophyses expanded.
12. Maxillae, premaxillae, and prevomers edentate.
13. Cranial roofing bones well ossified.

Griffiths (1959) accorded considerable taxonomic weight to the presence or absence of epicoracoidal horns in showing relationships among the genera placed in the Brachycephalidae [= Atelopodidae; Dendrobatidae; and Leptodactylidae (in part)] by Noble (1931). Allophryne possesses well-developed, free epicoracoidal horns, such as those found in the Hylidae, Centrolenidae, Leptodactylidae and Bufonidae.

The presence of intercalary elements in the digits is characteristic of the Centrolenidae, Hylidae, Phrynomeridae, Pseudidae, and the rhacophorine ranids (including the Hyperoliidae). This element is bony in the pseudids and cartilaginous in the other families. Phrynomerids and rhacophorine ranids lack epicoracoidal horns and have firmisternal pectoral girdles. Centrolenids are small, delicate, arboreal frogs having poorly ossified skulls and fused tarsal bones, but agree with Allophryne in having T-shaped terminal phalanges.

Fig. 2. Dorsal (a) and lateral (b) views of distal phalanges of third finger of Allophryne. × 40.

Only the presence of intercalary cartilages (Fig. 2) suggests relationship of Allophryne to the Hylidae. The T-shaped terminal phalanges suggest affinities with centrolenids, elutherodactyline leptodactylids, or certain "brachycephalid" frogs. Griffiths (1959) clearly showed that Noble's Brachycephalidae was a polyphyletic assemblage. No hylid genus is edentate, and none has either T-shaped terminal phalanges or the unusual dorsal spinules. Perhaps the presence of intercalary cartilages is not indicative of relationship but instead is a parallelism (or convergence) in Allophryne and genera of the Centrolenidae.

CRANIAL OSTEOLOGY