64 



Male somewhat smaller than female, and having the urosome considerably 

 more slender. Last pair of legs very large, with the right leg somewhat longer 

 and much more slender than left, its penultimate joint rather narrow and produced 

 at the base outside to an acute lappet, terminal joint forming a strong curved 

 claw, with a thumb-like projection at the base inside; penultimate joint of left 

 leg much tumefied, but quite simple, without any processes or spinules, terminal 

 joint carrying a row of 4 rather small leaf-like appendages outside, and at the 

 tip 2 short, juxtaposed claw-like lamellse. 



Colour. Body in both sexes extremely pellucid, with a very faint 

 yellowish tinge. 



Length of adult female 0.95 mm., of male 0.85 mm. 



Remarks. This species is easily distinguished from the preceding one by 

 its more slender form, the perfect symmetry of both the last segment of the 

 metasome and of the genital segment, and finally by the structure of the last pair 

 of legs in both ^exes. The form recorded -by Th. Scott from the Scottish coast 

 as 8. gyrans, Giesbrecht, is identical with the present species, as proved by the 

 examination of a specimen kindly sent to me by that author. The female of the 

 Mediterranean species differs very conspicuously in the asymmetrical shape of 

 both the last segment of the metasome and the genital segment, the latter being 

 moreover distinguished by a number of irregularly arranged spiniform processes 

 not found in any of the northern species. In the male of that species, too, the 

 last pair of legs, as figured by Dr. Giesbrecht, exhibit well marked differences from 

 those in the present species, which more resemble those in -8. minor of Scott. 



Occurrence. I observed this form, many years ago, in a single locality 

 on the west coast of Norway, viz., Eggesbonses, south of Aalesund. It occurred 

 here not unfrequently at a depth of a few fathoms, on a sandy bottom covered 

 with a thin layer of dark mud; and it was several times watched in the living 

 state. Its movements are rather curious, constituting a perfectly regular whirling 

 run, in which the body is kept in a horizontal attitude just above the bottom. 

 For this reason I assigned to it the provisional name of Typhloealanus gyrator, 

 the generic name referring to the entire absence of visual organs. The same 

 peculiar manner of motion is also mentioned by Dr. Giesbrecht in the Mediter- 

 ranean species, and is most probably common to all the species of this genus. 



Distribution. Scottish coast: Loch Fyne, Firth of Forth (Scott.) 



