Astylozoon pyriforme is a stalkless peritrich whose ciliature is restricted to the oral region and reduced to a few aboral bristles at the posterior pole. As in other peritrichs, the infraciliature is located in two zones, oral (peristome and infundibulum) and aboral (trochal band and scopule). We also observed an epistomial membrane located in the region where the peristomial infraciliature begins, to the right of the haplokinety. The myonemic system of this ciliate has three parts: an oral myonemic ring, a peristomial myonemic network, and longitudinal myonemes. The argyrome consists of 35 to 40 thin concentric striations that surround the cell but not the peristome. During the stomatogenic process, the germinal kinety and the haplokinety are the origin of the new buccal structures, as in other peritrichs.

The aim of this study is to establish possible associations between temperature, salinity and egg and larval abundance, and the biochemical composition of wild ferthsed eggs and larvae of marine fish species. Eggs and larvae of the most abundant species at each station at the time of sampling were collected during 2 surveys carried out from 25 March to 14 Apnl 1995 (MPH-95) for collecting eggs and from 30 May to 16 June (SEFOS-95) for collecting larvae. Both surveys were carried out on the N-NW coast of the Iberian Peninsula. Egg size, egg abundance, egg stage, temperature and salinity explained a small variance in the high variation observed within and between stations in protein, carbohydrate and lipid content of the eggs in both Trachurus trachurus and Scomber scombrus. Conversely, protein, carbohydrate and lipid content of larvae in Sardina pllchardus, Engraulis encrasicolus and T trachurus seemed to vary according to either larval body length, temperature, salinity a n d o r larval abundance. Protein, carbohydrate and lipid content increased as larval body length increased for the 3 species. However, a percentage of lipid and protein in the larvae of the 3 species varied according to prevailing buoyancy conditions. An increment of larval lipid percentage and a reduction of larval protein percentage was observed as temperature increased and salinity decreased, the opposite case causing an increase in protein percentage and a decrease in lipid percentage of the larvae. This trade-off between protein and lipid production is interpreted as a mechanism to achieve optimal larval buoyancy.

The somatic and buccal infraciliature of Lagynus elegans are described, and aspects of its division and conjugation are reported. Its somatic infraciliature is made up of 37–46 meridianal kineties composed of isolated kinetosomes that have thick and long kinetodesmal fibers. In the anterior zone of the cell, the circumoral infraciliature can be observed: it is composed of short, slightly oblique kinetal segments, which are formed of three kinetosomes each. The brosse of this species consists of 3 or 4 groups that possess 4 to 6 ciliated kinetosomes each; these kinetosomes lack kinetodesmal fibers. On the apical pole of the cell, surrounding the oral opening, a crown of nematodesmata is observed; these nematodesmata are connected to each other by a fibrillar structure. Taking into account these features, we propose that this genus be transferred from the order Prostomatida to a new family, Lagynidae, of the order Prorodontida.

We studied the composition distribution and dynamics of ciliated protozoan communities as well as their relationships with the physical-chemical characteristics of their environment in the River Henares (Central Spain) .A total of 67 species belonging to 54 genera were identified . Thirty-four species were subjected to statistical treatment using absence-presence data . Principal component analysis reduced the number of variables to two factors which accounted for 84 .73% of total variance . The first axis grouped non-conservative variables which strongly depended on biological activity. This axis was identified with `nutrient status and pollution level' . In contrast the second factor included conservative variables poorly influenced by the activity of organisms . This axis was identified with the `water mineral content' . From the arrangement of different species of ciliates with regard to these two factors and using non-hierarchic cluster analysis we established three different groups with respect to each factor.The saprobiological characterization of the different sampling points indicated that three different stretches can be distinguished in all seasons and we propose some tentative relationshps between chemical and biological variables which characterize the different levels of saprobity in this river.

The morphology and morphogenesis of two species of the genus Lernbadion, L. Iucens and L. bullinurn, are described. In both species, left and right ventral kineties converge behind the mouth forming a postoral suture. Buccal infraciliature is formed by one polykinety and two very close paroral kineties (inner and outer). During stomatogenesis, the new oral structures originate from the paroral kineties. The inner paroral kinety forms the new adoral polykinety and regenerates the outer paroral kinety of the proter, while the paroral kineties of the opisthe originate from the outer paroral kinety of the parental cell. Somatic proliferation starts before the stomatogenesis at the equatorial level of the cell, and extends towards the poles forming an equatorial band. Two large invariant zones, anterior and posterior, remain in the dividing cell. Moreover, the kinetodesmal fibers disappear in the proliferation band during the bipartition (fission) process.