A new species of Leptorhynchoides Kostyler 1924 (Acanthocephala) from the pirate perch, Aphredoderus sayanus (Gilliams).

Leptorhynchoides aphredoderi sp. n. is described from specimens recovered from pirate perch, Aphredoderus sayanus, collected in southeastern Louisiana. The new species is distinguished by having more longitudinal rows of proboscis hooks (15 to 18) than any other species of Leptorhynchoides. It differs additionally from L. thecatus and L. plagicephalus in having a shorter trunk, proboscis, proboscis receptacle, and proboscis hooks. Eggs of the new species are much larger than those of L. thecatus. L. aphredoderi differs further from L. plagicephalus in having fewer proboscis hooks in each longitudinal row and wider eggs. L. aphredoderi differs additionally from L. campbelli in having more proboscis hooks in each longitudinal row and much longer eggs.

Morphological variation of Moniliformis moniliformis (Bremser 1811) Travassos 1915 and Moniliformis clarki (Ward 1917) Chandler 1921.

A two-way fixed model analysis of variance was used to test Moniliformis moniliformis and M. clarki for inter- and intraspecific differences with respect to 7 morphological characters used to distinguish species of the genus. M. clarki was sexually dimorphic in more characters than was M. moniliformis when specimens from their usual definitive hosts, Spermophilus tridecemlineatus and Rattus norvegicus, respectively, were compared. More characters were sexually dimorphic in both species reared in hamsters, Mesocricetus auratus, than in their usual definitive hosts or M. clarki from rats. Moniliformis clarki and M. moniliformis (n = 25 each sex, each species) from their usual hosts were significantly different at the 1% level in 6 of 7 characters studied. Further M. clarki of either sex from ground squirrels did not differ significantly in any of the 7 characters from those of the same sex from rats. When reared in hamsters, the range in number of longitudinal rows of proboscis hooks of female M. moniliformis included that of M. clarki, but the 2 species were distinct in each of the other features which distinguished them in rats and ground squirrels.