Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Food history of Eleginops maclovinus (Valenciennes, 1830) (Teleostomi: Nototheniidae) in Mehuin, Chile?. Three hundred and sixty three specimens of Eleginops maclovinus (Valenciennes, 1830) were studied to know its food habits in the river Lingue mouth (Chile, 39°25?S; 73°10?W). Male-female proportion (%) is shown for every month. The sample statistically shows size class of males between VII and XI and in the females between VIII and XIV in comparison with other studies (Gosztonyi, 1974). 44% of the stomach samples were empty. Stomach contents were 84.32% of weight in animals and 11% in plants, mainly algae. Most abundant animals were crustacea. Figurae in relation with the fishes sample characteristics and in relation with stomach contents are presented. As conclusions, E. maclovinus is an omniporous species feeding principally on bentic animals.

?Spermatogenesis of Pheretima hawayana (Rosa) (Oligochaeta, Megascolecidae)?. The spermatogenesis of Pheretima hawayana (Rosa) was studied from an eminently cytogenetic point of view, leaving aside the classic histological techniques. Instead a previously tested and modified air-drying technique for Oligochaeta was employed. It was determined that there is a normal developmental process from protogonia and spermatogonia. These cells undergo 5 synchronous premeiotic mitosis (spermatogonic groups of 2, 4, 8, 16 cells and spermatocytes I of 32 elements) and the meiotic division (spermatocytes II and spermatids 64 and 128 elements respectively) leading to the formation of viable gametes. This last fact was confirmed by direct observation of the spermatozoons in the seminal receptacles or spermathecae.

Histological description of the oropharyngeal structures in the gastropod mollusk Ampullaria canaliculata Lamark?. An histologic description is made of the different structures of the pharyngeal bulb in the snail Ampullaria canaliculata. We do emphasize the variable activity of cavitary surface epithelium. Its morphologic and secretory characteristics change according to the zonal function and specially in relation to the development of the masticatory structures.

Epigean coleopteran taxocoenoses of the relict forest of Fray Jorge, Chile?. In this work a study is made on the individuality of the relict forest at Fray Jorge National Park; its independence from the surrounding types of vegetation, including the regional climax situation; and its biogeographical links with the Valdivian forest from which it could have derived. lts individuality and independence are shown through similarity criteria (i.s.: Jaccard, Winer and Horn indexes), as well as fidelity, relative abundance relations, time-space constancies and temporal schemes of specific diversity (Shannon index). It is concluded that the hypothesis stating the individuality and independence of the forest is true. Also, a consideration is made in relation to the epigean Coleoptera as having a paleantartic origin, corresponding to the one presently existing in Central Chile, with scarece direct actual links with the valdivian forests.

Seasonal variation of the thecate dinoflagellates and tintinnids from Estero de Castro, Chiloé, Chile?. The analysis of the seasonal variations of thecate Dinoflagellates and Tintinnids found in nearly 400 plankton samples collected fortnightly in six fixed stations, during 14 months in the Estero de Castro (Chiloé, Chile) is presented. The results reveal a strong seasonal variation of specific diversity and number of cells by each species, both in the interior and exterior areas as defined in this paper.

Effect of oxytocin and angiotensin II on the unidirectional flow of water in toad skin?. The diffusional permeability to water (Pdif) was measured in toad skin using tritiated water. The effect of unstirred layers, previously described in the literature, was assessed, and increases in Pdif brought about by treatment with oxytocin and angiotensin II were demonstrated. It was also found that theophylline, an inhibitor of the enzyme phosphodiesterase, also increases Pdif in this preparation, thus providing additional evidence of the involvement of cyclic AMP in the effects of these hormonal agents on water permeability.

Histological modifications in the final evolutionary stages of the enamel organ in humans and rats?. We have found in a new born baby a close relationship between big blood sinus, the intermediate layer and the ameloblastic epithelium. In white rats we do see a similar, but less complex vasculo-epithelial relation, in the perinatal stage.

?Brief references to the external bio-ecological and morphological systematics of triatomines, especially Triatoma infestans and Triatoma sordida? This is an introduction to the subject assigning special importance to the Tryatomine bugs, among which are found vector species of T. cruzi. Through a quick and systematic survey of the Order Hemiptera, it is established that in Bolivia at this date we have identified three genera with thirteen species, of which two are responsible for transmitting ?trypanosomiasis americana? throughout the greater part of the national territory. The genus Triatoma is described, with special stress on external morphological characteristics, geographic distribution and numerous bioecological data. The species Triatoma infestans and Triatoma sordida are also described in detail considering external morphology, biology and ecology. We note that the micro hymenoptera Telenomus fariai is incapable of achieving an affective biological control of the mentionned species due to the fact that its diurnal habits prevent it to penetrate in cracks and dark corners where the vector?s eggs may be found. The paper ends with a dichotomic keys for genera and species of Tritomine from Bolivia.

Maternal-child relationship and recognition in Otaria flavescens (Shaw) (South American sea lion) and reactions of subadult males to cubs?. The mother-infant diad of Otaria flavescens normally lasts about a year or less but can sometimes remain together for a longer period up to two years. The mother-young recognition is already mutual before 24 hours after birth has elapsed and is made by acoustic and olfactory cues. Subadult males react to isolated pups and to their vocalizations, attacking, biting, shaking and sometimes killing them.

?On some aspects of the captive behavior of Xenodon merremii (Wagler) (Ophidia: Colubridae)?. The behaviour of Xenodon merremii, one of the commonest snakes of the central and northern part of Argentina, had hardly been observed until now. This paper presents a set of observations about the young and adults? ethology which provided some tentative conclusions. We analize here the feeding behaviour, where we found that the predilection of this reptile in feeding on toads of the genus Bufo has ethologie bases; we also did observations about the ?after-food-cleaning? behaviour, and about the inhibition of canibalism, probably caused hy glandular secretions. This paper also analyzes the behaviour before and during copulation, in which the female has always a passive attitude. The egg-laying and the birth are also described. The youngs provided an interesting material to study the development of territoriality and aggressiveness, and data about the feeding behaviour also.