00386nas a2200121 4500008004100000245006100041210005500102300001200157490000700169100001900176700001700195856005200212 1971 eng d00aCura azteca, nuova specie di planaria del Messico0 aiCura aztecai nuova specie di planaria del Messico a477-4810 v501 aBenazzi, Mario1 aGiannini, E. uhttps://continenticola.myspecies.info/node/184104352nas a2200145 4500008004100000022001400041245008000055210006900135260001300204300001200217490000600229520390100235100001804136856005204154 1971 eng d a1432-193900aThe distances travelled by drifting invertebrates in a Lake District stream0 adistances travelled by drifting invertebrates in a Lake District c1971 Dec a350-3790 v63 a

The distances travelled by drifting invertebrates of 18 taxa were investigated at sites 3 and 4 in the Wilfin Beck, a small stony stream in the English Lake District. Fifty invertebrates of the same taxon were released into the stream at increasing distances upstream from a large net which caught all invertebrates drifting downstream.The relationship between the catch in the net (Y x ) and the distance from the release point to the net (X m) was well described by the regression equation:[Formula: see text] whereR is the constant relative rate of return of invertebrates to the bottom of the stream, andA=Y 0=number of invertebrates released at each point=50. Values ofR, the mean drift distance ([Formula: see text] m), and the distance (X p m) travelled byP% (1%, 10%, 50%) of the drifting invertebrates were calculated for each taxon at different modal water velocities. Values ofR,[Formula: see text] andX p were fairly constant for each taxon at a particular modal water velocity, and were not significantly affected by the source of the experimental animals (benthos or drift), by changes in illumination (daylight or darkness), or by seasonal changes, including water temperature.The experimental taxa at site 4 were divided into the following three groups according to their ability to return to the bottom: 1. Polycelis felina, Ancylus fluviatilis, Chironomidae, Eliminthidae, andAmphinemura sulcicollis. Values ofR,[Formula: see text],X p not significantly different from those obtained for dead invertebrates, which were removed from the drift by chance effects. 2. Protonemura meyeri, Leuctra spp.,Chloroperla spp.,Rhithrogena semicolorata, Simulium spp. Values ofR,[Formula: see text],X p not significantly different from those obtained for dead invertebrates at modal water velocities ≧19 cm/sec. At low velocities (10-12 cm/sec),R was significantly greater and[Formula: see text],X p significantly smaller than values obtained for dead invertebrates. 3. Erpobdella octoculata, Gammarus pulex, Hydropsyche spp.,Ecdyonurus venosus, Ephemerella ignita, Baëtis rhodani. Values ofR,[Formula: see text],X p significantly different (R greater,[Formula: see text] andX p smaller) from those obtained for dead invertebrates. The exponential law was not a good model for experiments with cased caddis larvae (Agapetus fuscipes and a mixed group ofSericostoma personatum, Drusus annulatus, Potamophylax cingulatus). Larvae sank rapidly after release and drifted over very short distances.Values ofR for each taxon were significantly higher at site 3 than at site 4, and the more rapid return at site 3 was presumably due to dense stands of aquatic macrophytes. The increase inR was greatest forSimulium spp. andE. ignita.The relationship between[Formula: see text] and modal water velocity (V cm/sec) was well described by the regression equation:[Formula: see text] wherea andb are constants. The relationship betweenR andV, orX p andV, was described by similar equations. Values ofa andb were calculated for each taxon at sites 3 and 4.The drift distance was also investigated by blocking the total drift and taking drift samples at several stations downstream from the blockage. Drift rate was markedly reduced immediately below the blockage and then gradually increased downstream until it was similar to that recorded before blocking. The mathematical model developed from the detailed experiments was a good fit to the results of the blocking experiments.The behaviour of the drifting invertebrates and their ability to return to the bottom are discussed. From the results of the present study and those of other workers, it is concluded that the mathematical model is a good model for invertebrate drift. The implications of the model are discussed, especially the relationship between drift rate and water velocity, and the proportion of the benthos in the drift.

1 aElliott, J, M uhttps://continenticola.myspecies.info/node/171200384nas a2200109 4500008004100000245008300041210006900124260001100193490000700204100002000211856004300231 1971 eng d00aCentriole morphogenesis in developing ciliated epithelium of the mouse oviduct0 aCentriole morphogenesis in developing ciliated epithelium of the c1971//0 v511 aDirksen, E., R. uhttp://dx.doi.org/10.1083/jcb.51.1.28600462nas a2200109 4500008004100000245014100041210006900182260002200251300000900273100001800282856005200300 1971 eng d00aThe systematic and biogeographical relationships of some Dugesia species (Turbellaria, Tricladida) from Central and South America0 asystematic and biogeographical relationships of some iDugesiai s aNew Yorkc10/1971 a1-251 aBall, Ian, R. uhttps://continenticola.myspecies.info/node/139100407nas a2200109 4500008004100000245007500041210006900116300001000185490000700195100002200202856007300224 1971 eng d00aBottom fauna of streams in spring season in relation to food of fishes0 aBottom fauna of streams in spring season in relation to food of  a73-770 v231 aAli, Syed, Rashid uhttp://www.ephemeroptera-galactica.com/pubs/pub_a/pubalis1971p73.pdf00416nas a2200121 4500008004100000245008000041210006900121300001000190490000700200100001800207700001700225856005200242 1971 eng d00aDescrizione della planaria Dugesia lanzai, n. sp. del Kenya (Africa)0 aDescrizione della planaria iDugesia lanzaii n sp del Kenya Afric a20-350 v781 aBanchetti, R.1 aDel Papa, R. uhttps://continenticola.myspecies.info/node/139301170nas a2200145 4500008004100000022001400041245008500055210006900140260002900209300001200238490000600250520069000256100002100946856005700967 1971 eng d a1463-640900aDugesia sudanica sp. n. from Africa (Turbellaria, Tricladida, Paludicola)0 aiDugesia sudanicai sp n from Africa Turbellaria Tricladida Palud bBlackwell Publishing Ltd a37–410 v13 a

A small sample of freshwater triclads from streams and pools of the Gebel Marra volcanic massif in the Western Sudan was examined by the author. All specimens showed the general features characteristic of triclads within the “arrow-headed” Dugesia group. The specimens serially examined show a number of less conspicuous features not agreeing with those described in other Dugesia forms reported from African localities. A description has been given and as a new species name Dugesia sudanica has been proposed. The new species would, according to the author, represent a further “microspecies” within the “superspecies”Dugesia gonocephala.

1 aDahm, Anders, G. uhttp://dx.doi.org/10.1111/j.1463-6409.1971.tb00711.x