58 TERRESTRIAL CARBONIFEROUS ARACHNIDA. 



observed, yet the carapace of AntJvracomartus is, generally speaking, like that of 

 Anthracosiro and Trigonotarbus. 



Of Brachypyge, as exemplified by the type species B. carbonis, only the dorsal 

 surface of the opisthosoma is known. Of the second species, which has been referred 

 to the genus, namely, I', celtica, only the ventral area of the opisthosoma has been 

 described and figured. These two species resemble each other, and differ from 

 the rest of the Anthracomarti in the production of the angles of the pleural plates 

 into spiniform processes. The two species are probably, but certainly not closety, 

 allied, and there are good grounds for regarding them as distinct genera. There 

 seem to me to be no justifiable reasons for assuming that the anterior sterna of 

 the opisthosoma of B. celtica have been wrongly depicted. If correctly drawn, 

 they differ greatly from the corresponding plates of Anthracomartus. On the 

 strength of this difference, supplemented by the peculiar formation of the margins 

 of the pleural plates, above alluded to, I am now disposed to separate Brachypyge 

 from the family Anthracomartida?, and erect for its reception the family Braclry- 

 pygidas. For Anthracosiro and Trigonotarbus the name Anthracosironida? may be 

 retained ; while the Eophrynidas will comprise Eophrynus, Kreischeria, and 

 Aphantomartus. 



The four families may be distinguished as follows : 



a. Margins of the pleural laminae concave with spiniform angles ; pleural laminae large 

 and divided as in the Anthracomartidae, but the anterior sterna of the opisthosoma, 

 where known, not enlarged and backwardly produced . . Brachypygidee. 



a . Margins of the pleural laminae of the opisthosoma convex, the angles not produced. 

 b. Carapace of prosoma not markedly silicate except posteriorly ; its lateral and 

 anterior portions sloped gradually or steeply downwards to the margin. 

 c. Opisthosoma with very large pleural laminae, each of which is divided into 

 an external and an internal moiety by a sulcus visible on the dorsal and 

 ventral sides ; the anterior sternal plates swollen and produced back- 

 wards in the middle line and furnished on each side with a deep depression ; 

 the posterior sternal plates produced forwards and mesially angular 



An thracomartidse . 



c . Opisthosoma with its pleural laminae small or moderate and undivided, 



not defined by a sulcus on the ventral side ; anterior sterna small, not 



backwardly produced and not deeply impressed laterally ; posterior sternal 



plates not angularly notched in the middle line . . Anthracosironidie. . 



V . Carapace of prosoma transversely sulcate ; its lateral portions extended as a 



horizontal sulcate lamina considerably beyond the elevated median portion ; 



opisthosoma with pleural laminae undivided, its sterna as in the Anthraco- 



sironidse ....... Eoplirynidm. 



Family Brachypygid/e, nov. 



Characters as above. 



I refer the two known species of this family to the following genera, which may 

 be distinguished thus : 



