B. I. Pococh — Tlie Carboniferous Arachnid Anthracosiro. 405 



Y. — FUETHER EeMARKS TIPON THE CARBONIFEROUS ARACHNID 



Anthbacosieo, with the bescription of a second species 



OF the genus. 



By E. I. PococK, F.Z.S., of the British Mufseum (Natural History). 



IN the Geological Magazine for June of this year I proposed the 

 new specific and generic names Anthracosiro woodwardi for 

 a Carboniferous Arachnid represented in the British Museum by 

 a single specimen (No. 1551) from Coseley, near Dudley, that 

 formerly belonged to the collection of Mr. Henry Johnson. A 

 further communication from Dr. Fric, of Prague, drew my attention 

 to three additional specimens, with the same history, numbered 1554, 

 1555, and 1556, and ticketed Eophrynus, sp. nov. No. 1555 is 

 the under-side of a scorpion, without the tail ; the others are 

 referable to the genus Anthracosiro. 



No. 1554 appears to belong to the same species as the type of 

 Anthracosiro woodwardi. Unfortunately the prosoma is so crushed 

 that no details of its structure can be deciphered, beyond a con- 

 fusedly radial arrangement of certain of its component parts 

 indicating the disposition of the coxee, and a broad central 

 longitudinal ridge representing presumably the median area of 

 the carapace. The position and length of the legs is also shown ; 

 but nothing new concerning their structure can be made out. The 

 rest of the fossil consists of the terga of the opisthosoma, the entire 

 ventral surface being wanting, except apparently the inturned 

 portion of the eighth, which exhibits very clearly the subcircular 

 anal plate (tergum of the tenth segment), surrounded by the narrow 

 and annuliform united tergal and sternal elements of the ninth. ^ 



As in A. woodwardi, the external portions of the laiuiuas of the 

 third, fourth, fifth, and sixth terga are defined by a groove and 

 upturned ; and no joint is visible between the laminge of the eighth 

 and the median area of the tergum from which they arise. Except 

 that the hinder borders of the posterior terga are rather more 

 recurved than in the type of A. woodwardi, there is very little 

 difference between the two fossils ; and, without a series of 

 specimens to test the constancy of this feature, it would be rash 

 to attach a specific value to it.- 



1 I am unable to satisfy myself absolutely whether the two halves of the nodule 

 exhibit the dorsal side of the terga and the impression of the same or the ventral 

 surface of these plates and theii- impression ; but I incline to the latter opinion on 

 account of the distinctness of the anal sclerite and the lesser definition in detail 

 presented by the hah of the fossil sho-«dug what is either the dorsal surface of the 

 terga or the impression of their under-side. So far as the structure of the plates is 

 concerned, a definite decision on tliis point is a matter of no great moment ; but the 

 "\dew here adopted carries the conclusion that the sternal elements have been entirely 

 removed ; whereas, according to the other hypothesis, the sterna remain in all 

 probability buried in the stone. 



2 In the description of A. ivoodioardi I stated that a pair of tubercles is present 

 upon the terga. This is an error. The tubercles appear upon the half of the fossil 

 which is the impression of the dorsal surface. They therefore represent pits, not 

 tubercles ; and are doubtless to be referred to the paired muscular impressions 

 characteristic of the terga of many Aiachuida. 



