Jdlt 30, 1920 Vou VII, pp. 55-59 



PROCEEDINGS 



OF THE 



NEW ENGLAND ZOOLOGICAL CLUB 



NOTES ON TWO PACIFIC COAST AMBYSTOMIDAE 



BY EMMETT REID DUNN 



In the course of work on the Plethodordidae certain facts re- 

 garding the Ambystomidae have come to light, and they are here 

 offered. 



I am able to support Van Denburgh's contention (Proc. Cal. 

 Acad. Sci., (4), VI, p. 221) that Ambystonia tenehrosum Bd. and 

 Gir. and Triton ensatus Eschscholtz (Zool. Atlas, V, p. 6, pi. 22, 

 1833) are the same species. A skull of tenehrosum, compared 

 with the figure in the Zoologisches Atlas, shows a remarkable 

 similarity even in trivial details. The hyoids also are exactly 

 alike. Chondroius Cope (Amer. Nat., 1887, p. 88) is a synonym 

 of Dicamptodon Strauch (Mem. Acad. Sci., St. Petersbourg, (7), 

 XV, 4, 1870), as A. tenehrosum was the type species of Chon- 

 drotus. 



It would require a great deal more investigation to settle 

 finally the status of the generic relationship of Ambysioma, 

 Dicamptodon, and Linguelapsus. The hyoids of A. ensaium, 

 however, differ markedly from those of A. maculatum, A. opa- 

 cum, and A . tigrinum, all of which are quite alike. The larvae of 

 our eastern species have a fin-fold on the back as far as the 

 head. This is absent in ensaium larvae. 



