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Superfamily Arionoidea
This group of slugs has evolved from a family of primitive landsnails,the 
Endodontidae.Binneya,a genus form North-America,still has an extern shell.In the
European genus Geomalacus this reduced to an internal shell,while in the genus
Arion this is further reduced to granules.The mantle is located near the front
of the body,the pneunostome being in front of it.The tail end is rounded without
a keel.The foot is wide and the tentacles bearing the eyes have rounded tops.

Genus Geomalacus Genus Granulilimax Genus Hemphillia Genus Kootenaia Genus Magnipelta Genus Letourneuxia Genus Nipponarion Genus Nipponolimax Genus Pallifera Genus Prophysaon Genus Udosarx Genus Zacoleus Subfamily Binneyinae Genus Binneya Subfamily Ariolimacinae Genus Ariolimax Subfamily Anadininae Subfamily Oopeltinae Subfamily Arioninae Genus Arion Subfamily Ariolimacinae photo:Alex Wild Ariolimax californicus Cooper,1872 Body light yellow,mantle concolorous. Length 175-200 mm. In central California. A subspecies is A.c.brachyphallus,this slug has a shorter penis.

Ariolimax dolichophallus Mead,1943 Body light yellow,mantle concolorous. Length 150-180 mm. In coastal central California. photo: 2005 Eric Machleder

Ariolimax columbianus Gould,1851 Banana slug Body deep olive green,ochre,slate green,variable,with black spots varying from spots to blotches. Length 185-260 mm. In Alaska(Sitka),British Columbia,Washington,Oregon to California south the Salinas Valley. A subspecies is A.c.stramineus,this is in general a smaller thinner slug,is unspotted and has a smaller penis.There are also differences in the female reproductive organs. Its area of distribution is Ventura County;The Santa Cruz and Santa Rosa Islands off the coast northward to below the Monterey Bay.

Geomalacus maculosus Allman,1846 Animal grey,brown to black with many yellow or white spots,tentacles grey. Foot brown with dark stripes across a narrow fringe,the center part of the sole is clear with a yellow or grey band on both sides. Length about 55 mm. In Cork(Kerry);Ireland,Brittany,Northwest Spain and Portugal. photo:Official Killarney National Park website Subfamily Arioninae Arion ater Linnaeus,1758 European Black slug This slug has a long,wide body,a little rounded at the back and can have many colors.From orange to reddish brown to black. The foot fringe is usually reddish while the sole is grey. It can grow up to 150 mm.Mucus is white-yellow in orange species, it is colorless in dark species. The orange and reddish species tend to appear in warmer regions,than the darker species. When disturbed the animal contracts into a half round shape and moves from side to side.In the north of Europe it has an annual lifecycle.In late summmer or autumn eggs are laid,with hatch in springtime. Eggs are 5 x 4 mm in size,but variable,pearly white turning to yellowish brown. A cluster can have 150 eggs which hatch in 4-6 weeks.Young slugs are 10 mm, yellowish grey with a darker grey head and tentacles. In damp woods,meadows and gardens,in West- and Central-Europe,and North-America.

Arion rufus Linnaeus,1758 Formerly Arion ater and Arion rufus were considered species and subspecies but nowadays people generally consider them two different species.The difference is only visible through disection:A.ater has a more slender genital atrium than A.rufus. The colour of the animal is not a useful aid in identification.Arion ater can be blackish to red and Arion rufus can be reddish to blackish.

Arion lusitanicus Mabille,1868 Can also have different colors,greyish green,grey or brown,head and tentacles darker. Length 70-100 mm. In England,Portugal,France,Switzerland.

Arion fasciatus Nilsson,1822 A light colored slug,paler on the sides,pale grey to darker grey. The lateral stripes are dark grey.Tentacles black.The sole is greyish white. Juveniles are pale with black head and tentacles. Mucus colorless. Length 35-40 mm. In cultivated areas,it prefers damp places under shrubs.Feeds on funghi and decaying vegatation. In Northwest Europe and also in North-America.

Arion(Carinarion)circumscriptus Johnston,1828 About 3-4 cm and grey,darkgrey with dark spots.The lateral stripes are dark grey. The sole is whitish and the mucus is colorless. Eggs are laid from May to autumn and hatch in 4-5 weeks.They are 3 x 2 mm in size and yellow to amber colored.They are more flexible and translucent than in other species. In damp woods,small valleys,a flat country species. Very common in Northwest Europe,introduce in North-America.

Arion(Carinarion)silvaticus Lohmander,1937Wood slug About 1 3/4 inches(4cm),grey-brown.The sole is whitish and the mucus is colorless. It has a dark zone on the back and lives in shadowy woods.

Arion(Mesarion)subfuscus Draparnaud,1805Brown slug This slug is yellow-brown or grey-brown,darker on the back.Foot fringe is pale with dark transverse stripes.Sole yellowish-white with white specks. The mantle shield covers a third of the body.The animal is about 50-60 mm long. Mucus is yellow or orange. Eggs are variable in size 2.25-3.35 x 2.25 mm,white and leathery.They are laid in clusters of up to 50 eggs and hatch in 3-5 weeks. In forests through Europe.

Arion(Kobeltia)distinctus Mabille,1868 Is lighter colored than A.hortensis.Mucus is orange-yellow and sole orange. In gardens,parks and fields In West-and South-Europe,and North-America.

Arion(Kobeltia)intermedius Normand,1852 Animal pale yellowish grey,darker on the back,head dark.The center dorsal tubercles are yellowish-white.Foot fringe yellowish grey and sole yellow-white. Mucus yellow. Length 15-20 mm. In woods and fields where it feeds on fungi.

Arion(Kobeltia)hortensis Ferussac,1819 Animal small and slender,dark brown to grey with yellow-brown dots.A dark longitudinal band runs on both sides,sharp edged towards the back but blurs into pale grey towards the foot.The fringe of the foot is yellowish,sole yellowish to orange. Mucus colorless,body mucus pale to dark yellow. Length about 25-30 mm. In northern Europe they have a life cycle of a year.After breeding in summer, during autumn,winter and spring the young grow to mature within a year. During dry spells or freezing conditions A.hortensis can burrow under the ground till a depth of a metre. The eggs are 2.5 x 2 mm,opaque yellow and sticky.They are laid in clusters of up to 30 eggs.There may be a second or third cluster in 3 week intervals. In gardens,parks,fields and woods,very common. In north Europe,central Europe,also north France and Spain.Introduced in North-America.

Prophysaon andersoni Cooper,1872 Reticulate Taildropper The coloring of the slug can be variable:pale brownish,reddish grey or yellowish. The mantle is paler,usually with a pair of dark lateral bands, while the tentacles are darker colored.The footfringe is pale and the pneumo- stome close to the middle.Mucus is lemon yellow to orange.Fully stretched Prophysaon can be up to 6 cm. The animal lives in woods and gardens in damp conditions under logs,leaf litter, rocks and plants.In North-America and Canada.

Prophysaon boreale Pilsbry, 1948 Northern Taildropper

Prophysaon dubium Cockerell,1890 Papillose Taildropper Body dark and tapering,the sole is pale with grey edges.The mantle is fine papillose throughout. The color of the body is purplish gray,with various darker clouds,sometimes in two main bands on the mantle.The neck is lighter with some spotting. Length about 8 mm. In Washington. [photo:(c)William Leonard]

Prophysaon coeruleum Cockerell,1890 Blue-gray Taildropper Body and mantle blue grey,paler at the sides,with a white sole.The mantle is finely granulated,and is 7 mm long and 5 mm wide.The pneumostome is 2.5 mm.The body is sub-cylindrical and tapering. Length about 25-43 mm. In Washington and Oregon. [photo:(c)Kristina Ovaska]

Prohysaon foliolatum Gould, 1851 Yellow-bordered Taildropper [photos:(c)William Leonard]

Prophysaon humile Cockerell,1890 Smoky Taildropper [photo:(c)William Leonard]

Prophysaon(Mimetarion)vanattae Pilsbry, 1948 Scarletback Taildropper [photo:(c)William Leonard]

Pallifera dorsalis(Binney) Body ashy with shade of blue with an interrupted black line towards the back.Upper tentacles black, lower tentacles lighter.Shape of the body is narrow cylindrical.Base of foot white.Pneumostome very small. Length about 18 mm. In Ontario,VT,MA,PA,VA,MN,IN.

sub-family Binneyinae Binneya notabilis Cooper Shell depressed,oval,spire depressed,color pale yellow. Length 13.3 mm and width 8.9 mm. Animal whitish,with about 17 vertical rows on both sides of greyish blotches.These blotches are on the whole body.Tentacles and head greyish. In California.(extinct?).

Kootenaia burkei [ 2004 William Leonard] Distribution:Idaho(USA)

Hesperarion mariae Branson,1991 Distribution:Oregon(USA) [ 2001 William Leonard]

Hesperarion niger Cooper,1872 [ 2000 William Leonard] Distribution:California

Magnipelta mycophaga Pilsbry,1953 [ 2003 William Leonard] Distribution:British Columbia,Washington,Idaho,Montana.

Udosarx lyrata Webb,1959 [ 2000 William Leonard] Distribution:Idaho,Montana(USA).

Zacoleus idahoensis Pilsbry,1903 [ 2001 William Leonard] Distribution:Idaho,Washington,Montana(USA). Home