α. The oral armature consists on each side of a stout tooth and a transversely placed support.
Gen. 3. MACROBIOTUS, C. Sch. (Fig. [252]).
β. The oral armature consists on each side of a stylet-like tooth without support.
Gen. 4. DOYERIA, Plate.
II. The mouth-tube is separated from the muscular sucking pharynx by a short oesophagus.
Gen. 5. DIPHASCON, Plate (Fig. [255]).
B. Six short processes or palps surround the mouth, and two others are placed a little farther back.
Gen. 6. MILNESIUM, Doy.
1. Genus ECHINISCUS (= EURYDIUM, Doy.).—The dorsal cuticle is thick, and divided into a varying number of shields, which bear thread- or spike-like projections. The anterior end forms a proboscis-like extension of the body. Two red eye-spots. There are many species, and the number has increased so rapidly in the last few years that specialists are talking of splitting up the genus. E. arctomys, Ehrb.; E. mutabilis, Murray; E. islandicus, Richters; E. gladiator, Murray; E. wendti, Richters; E. reticulatus, Murray; E. oihonnae, Richters; E. granulatus, Doy.; E. spitzbergensis, Scourfield;[[381]] E. quadrispinosus, Richters; and E. muscicola, Plate, are all British. More than one-half of these species are also Arctic, and E. arctomys is in addition Antarctic. In fact, the group is a very cosmopolitan one. The genus is also widely distributed vertically, specimens being found in cities on the sea level and on mountains up to a height of over 11,000 feet.
