NEMATODOS DE ALGUNOS VERTEBRADOS DEL VALLE DEL MEZQUITAL, HGO.

Resumen

We found in the stomach of Didelphis mesamericana mesamericana, numerous
specimens of Physaloptera (Turgida) turgida and in the intestinal
caecum, Cruzia tentaculata: both parasites are very common in Mexican
opossum.
In the small intestine of a gray fox, Urocyon cineroargenteus scottii,
we found Toxascaris leonina. According to Yorke and Maplestone the males
present 25 pairs of papillae in their caudal end; in the specimens we examined
there were only 22 pairs. In the stomach of the same specimen (Urocyon cineroargenteus
scottii) lives a species of Physaloptera not yet determined.
We revise the description of the nematode Skrjabinoptera (Didelphysoma)
phrynosoma, which we have found in the intestine of Sceloporus spinosus.
According to Schulz we have placed this species in the new genus and
subgenus that the russian helminthologist established in 1927.
In regard to the geographical distribution of this species found in Phrynosoma
cornutum, according to Van Denburgh we know that it is limited to
the Northern part of the State of Sonora and to the South of the United
States; therefore we believe that the specimens studied by Ortlepp proceeded
from the mentioned regions and not from Brazil as he asserts in his excellent
monograph of genus Physaloptera.