74 



TERRESTRIAL CARBONIFEROUS ARACHNIDA. 



The cox;t3 of the five pairs of post-oral appendages radiate round tlie elongated 

 sternal area of the prosonia, which is about twice as long as Avide. Of the first 

 pair of appendages or chelicerse no details can be determined. Those of the second 

 pair, the first post-oral appendages or palpi, are normallj^ constructed and pediform, 

 consisting of six segments ; the remaining pairs are similar in form and segmenta- 

 tion and approximately similar in size, each consisting of the usual number of 

 seven segments. 



Ti/jx; Species. — Trhjonoldrhns jnlntsoni, sp. nov. 



Although in the structure of its carapace this genus presents greater resem- 

 blance to Aiitliraeomarlus than to Fjoplinjiiiix, it approaches much nearer to the 

 latter than to the former in the structure of the sternal plates of the opisthosoma, 

 especially of those in the region of the generative orifice. It also resembles 



Fig. 38. — Trigunotarbus juhnsoni, gen. et sp. ii. ; i'e.storation from several specimens, alumt six tiiiu's luit. 

 size. - Coal Measures ; Coseley , near Dudley. «., dorsal surface with appendages; ?)., lateral view ot 

 carapace, about eight times nat. size ; c , ventral surface; ; d., transverse section of the opistliosoma to 

 show the convexity of tlie ventral surface and the uptilted pleura;. 



Eoplirijnns in having the lamina) of this region undivided on the dorsal side, and 

 not differentiated by a sulcus from the rest of the sternal ])lates on the sternal 

 side of the opisthosoma. No doubt its nearest known ally is Anthracosiro, of 

 Avhicli the sternal surface of the o})isthosonia is unknown ; but Trujoiiotdvliis is 

 certainly generically distinguishable by the shape of the carapace and of the 

 laminge of the o})isthosoina, and by the aljsence of lateral constriction between the 

 prosoma and opistliosoma. 



Trigonotarbus johnsoxii, sp. nov. Plate III, fig. 4; Text-figure 38. 



Integument closely and tolerably uniformly granular. Carapace about as long- 

 as its own posterior Avidth, and a little longer than the anterior six terga of the 

 opistliosoma. Opisthosoma a little longer than wide; the terga subequal in length 



