Paruterine Organ Research Articles

Fine Structure of the Gravid Paruterine Organ and Embryonic Envelopes of Mesocestoides lineatus (Cestoda)

Mesocestoides lineatus tetrathyridia were removed from the body cavity of lizards, Anolis caroli- nensis, and fed to hamsters in which they developed to adults. Gravid proglottids were taken from feces for study. Intact proglottids or excised paruterine organs (PO) were processed by standard techniques for TEM. For SEM, PO contents were exposed by subjecting whole proglottids to freon cryofracture or sectioning in Paraplast. Gravid PO's were thick-walled with enclosed eggs distributed throughout a cellular matrix. The wall was of parenchymal origin, containing muscle bundles and various cellular products. Each egg consisted of an oncosphere enclosed by a double-unit oncospheral membrane and a syncytial cytoplasmic envelope containing an embryo- phore. A discrete outer envelope and capsule were absent. Eggs were separated by PO matrix cells with prominent nuclei, mitochondria, intercellular junctions, and much extracellular material. These matrix cells may be related ontogenetically to individual eggs and thus homologous to embryonic envelope cells normally lying outside the embryophore of other cyclophyllids. Some differences in embryonic envelopes presumably were associated with containment of all eggs in the PO which may eliminate the need for individual protective shells. Other components of the PO matrix such as large reticular bodies are of unknown significance.

Rhabdometra lygodaptrion n.sp. (Cestoda: Paruterinidae) from willow ptarmigan (Lagopus Lagopus albus) in northern Ontario, Canada

Rhabdometra lygodaptrion n.sp. from the small intestine of Lagopus lagopus albus (willow ptarmigan) taken at Cape Henrietta Maria, northern Ontario, Canada, is proposed. R. lygodaptrion is most similar to R. alpinensis, R. nullicollis and R. tomica but is shorter than all these three species and the cuticularized vaginal lining is characteristic. R. lygodaptrion differs from R. alpinensis in having a thicker, more robust cirrus sac and a larger number of testes and in lacking a vaginal sphincter. R. tomica and R. nullicollis have a pear-shaped cirrus pouch which narrows distally while that of R. lygodaptrion is equally wide along its length. In additon, R. nullicollis has a vaginal sphincter and an elongate, sinuous paruterine organ, which in R. lygodaptrion, is wider and more cone-shaped. R. tomica has fewer testes.

Baerietta allisonaen.sp. (Cestoda: Nematotaeniidae) from a New Zealand gecko,Hoplodactylus maculatus

Abstract Baerietta allisonae n.sp. is described from a gecko, Hoplodactylus maculatus Boulenger, from Stephens Island, New Zealand. On the basis of lack of tegumental spines, number of eggs per paruterine organ, and measurements of internal organs it is most similar to B. janickii (Hilmy, 1936) Douglas, 1958. It differs in size of scolex (201–336 pm wide in B. janickii, 160 µm wide in B. allisonae), size of suckers (84–168 µrn wide in B. janickii, 60 µm wide in B. allisonae), sizes of testes (63 × 46 µm in B. janickii, 30–40 µm wide in B. allisonae), and cirrus armature (unarmed in B. janickii, armed in B. allisonae). This is the second species of Baerietta reported from a lizard.