CRYPTOSTEMMID^. 37 



other legs are correspondingly short. The palpi, on the contrary, which are not 

 shown in the specimen of Arclixonieta, are of most unnsual length. 



Archseometa nephilina, sp. nov. Text-figure 11. 



Total length about 10 mm. ; carapace al)Out 8 nun. long, 2 mm. wide ; abdomen 

 about 7 mm. long, 2 mm. wide ; femur, trochanter, and part of coxa of first leg 

 4 mm., of second leg 7'5 mm., of third leg al)out 5 mm., of fourth leg 8 mm. 



Coseley, near Dudley. 



Type and only known specimen in the Collection of Mr. Walter Egginton. 



Onler UICINULEI, Thorell. 



Carapace or dorsal shield of the prosoma unsegmented, but with a movable 

 plate, the cucullus, jointed to its anterior border and overhanging the jaws in front. 

 Prosoma and opisthosoma united by a jointed waist, often marked by a lateral 

 constriction. The opisthosoma either not visibly segmented or composed in the 

 main of three very large segments, the last carrjang a small jointed tail-like 

 process, which is not always exposed ; sometimes a shorter segment is visible in 

 front of the first of the three large segments. 



It is needless to give a complete diagnosis of this order, derived from the 

 existing genera Cri/ptostemma and Crypt ocellus. For this, reference may be made 

 to Hansen's and Sbrensen's monograph of 1904. The characters briefly enumerated 

 above are taken from the known Carboniferous genera, and are sufficient to dis- 

 tinguish the Ricinulei from the other orders discussed in this Monograjjli. 



Famihj CiiYPToSTEMMiDyE, Westwood. 



1874. Gnjptostemmidii', J. O. WestwooJ, Thes. Eut. Oxon., p. 210. 



1884. Poliocheridx, S. H. Scudder, Proc. Amer. Acad. Arts Sci., vol. xx, p. 16. 



1890. Poliocheridce, S. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 444. 



1892. Cnjptostemmidx, T. Thorell, Bill. Sveusk. Vet.-Akad., vol. xvii, 4, No. 9, p. 9. 



1904. Cnjidostemmatoldie, H. J. Hauseu and W. Soreusen, On Two Orders of Araelinida, p. 144. 



I provisionally refer the Carboniferous genera of this order to the family 

 Cryptostemmidse, which has the characters of the order. 



The two genera here admitted may be distinguished as follows : 



a. Opisthosoma elongate, narrowed posteriorly, not consisting mainly of three large 

 segments ; cucullus transversely suboblong, markedly wider than long. Citrcnlioides. 



a. Opisthosoma shorter, widely rounded posteriorly, composed mainly of three large 

 segments ; cucullus large, nearly as long as its basal width. . . PoUochera. 



