Entries to the 2013 Nikon Small World photomicrography competition are wonderful (as always, see our previous coverage of this fantastic competition), but some of this year's submissions got us wondering: are those truly small things that scientists see when peering through the microcope, or are they actually alien lifeforms?

Arturo Agostino, Reggio Calabria, Italy
Navicula variolata (diatom), Darkfield 400x

Mark Bateman, Berrien Springs, Michigan, USA
Nepeta cataria (catnip), Darkfield, Focus Stacking 40X

David Forest and Alison Sweeney, UC Santa Barbara, Neuroscience Research Institute Santa Barbara, California, USA
Deep sea amphipod, Brightfield

Jaime Gomez-Gutierrez, Centro Interdisciplinario de Ciencias Marinas La Paz, Baja California Sur, Mexico
Benthic fish egg cluster, Stereomicroscopy 6.6X

Alexander Gow and Cherie Southwood, Wayne State University, Department of Genetics Detroit, Michigan, USA
Mouse inner ear from a Claudin 11-null mouse reveals the distribution of tight junctions (blue), Brightfield 65X

Zhong Hua, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine Baltimore, Maryland, USA
Peripheral nerves in E11.5 mouse embryo, Confocal 5X

Gabriel G. Marins and Rob Bryson-Richardson, Centro de Biologia Ambiental/Faculdade de Ciencias Universidade de Lisboa Lisbon, Portugal E13 quail embryo 0.5X

Alvaro Esteves Migotto, Universidade de São Paulo, Centro de Biologia Marinha São Paulo, São Paulo
Brazil Marine worm, Stereomicroscopy, Darkfield 20X

Bryan A. Millis, National Institute on Deafness and Other Communication Disorders, Laboratory of Cell Structure and Dynamics, National Institutes of Health (NIH) Bethesda, Maryland, USA
Small intestinal section from a mouse expressing GFP-tagged non-muscle myosin II Large format image stitch, swept-field confocal fluorescence microscopy 200X

Rogelio Moreno Gill, Panama City, Panama, Panama
Micrasterias radiosa (algae), Polarized Light with Lambda Plate 40X

Somayeh Naghiloo, University of Tabriz, Department of Plant Biology, Faculty of Natural Sciences Tabriz, East Azarbayedjan, Iran, Islamic Rep. Asperugo sp. female flower, Epi-illumination 10X

Fabrice Parais, DREAL de Basse-Normandie Caen, France
Abdominal segments of Diptera blephariceridae larvae, Stereomicroscopy 40X

Liza Roger and Gareth Lawson, The University of Western Australia - Oceans Institute Perth, Western Australia,
Australia Clione (Pteropoda:Gymnosomata), Stereomicroscopy 10X

Mark A. Sanders, University Imaging Centers, University of Minnesota Minneapolis, Minnesota, USA
Clam glochidia (larva), Confocal, Autofluorescence 60X

Andreas Schmidt-Rhaesa, Corinna Schulze and Ricardo Neves, University Hamburg, Zoological Museum Hamburg, Germany
Actinarctus doryphorus (marine tardigrade), autofluorescence of cuticle, Confocal 40X

Laure Twyffels and Benoît Host, Université Libre de Bruxelles (ULB), Center for Microscopy and Molecular Imaging (CMMI) Gosselies, Belgium Enteric valve of Patawatermes nigripunctatus, a humivore termite belonging to the Apicotermitinae subfamily, Confocal, Autofluorescence 20X

Wim van Egmond, Micropolitan Museum Berkel en Rodenrijs, Zuid Holland, The Netherlands
Chaetoceros debilis (marine diatom), a colonial plankton organism, Differential Interference Contrast, Image Stacking 250X