PLATE 2 
Fig. 2. Skull of Phrynosoma douglassi douglassi (Zool. Dept.). Note 
the rudimentary occipital horns; the lack of spines on the jugal elements; 
the large supratemporal openings; and the position of the nasal openings. 
x 1%. 
Fig. 8. Skull of Phrynosoma blainvillei frontale (Zool. Dept.). Note 
the well-developed occipital and temporal horns; the interoccipital horn; 
the spines on the jugal elements; the supratemporal openings; the position 
of the pineal foramen; and the position of the nasal openings. X 114. 
Fig. 4. Skull of Phrynosoma blainvillei blainvillei (Univ. Calif. Mus. 
Vert. Zool., no. 272). Note the well-developed occipital and temporal 
horns; the interoccipital horn; the spines on the jugal elements; the 
supratemporal openings; the position of the pineal foramen; and the 
position of the nasal openings. X 114. 
Fig. 5. Skull of Phrynosoma platyrhinos (Univ. Calif. Mus. Vert. Zool., 
no, 1301). Note the short occipital and temporal horns; the spines of 
the jugal elements; the rudimentary spines of the maxillaries; the supra- 
temporal openings; and the position of the nasal openings. X 114. 
Fig. 6. Skull of Anota maccalli (Univ. Calif. Mus. Vert. Zool., no. 
1006). Note the long, conical occipital horns; the well developed second 
temporal horns; the spines of the jugal elements; the well developed 
spines of the maxillaries; the closure of the supratemporal openings; the 
dome-shaped parietal region; and the position of the nasal openings. 
xX 1%. 
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