312 Mr. R. Kidston on the Affinities of the 



tween the Scotch specimens and the plant he so fully describes 

 is afforded by the " receptaculum" which he says is " divided 

 into four slightly elevated lappets/' with an unevenly rough- 

 ened surface. 



This agrees in every respect with those shown on the upper 

 portion of the Pothocites from Eskdale (PL XII. fig. 16). 

 Their size also is almost similar. 



Whether each of the lobes of the little quadrate bodies re- 

 presents a sporangium, or the sporangium is four-lobed, I have 

 not sufficient evidence to decide. It is quite possible that the 

 sporangia were arranged in groups of four. It is, however, 

 evident that the u stellate bodies are formed by an outward 

 radial splitting of the four lappets, the split edges of which 

 eventually become deflexed. 



The shield-like structure (quadrats bodies) of Stur is 

 formed by the sporangia (or sporangium), and does not appear 

 to be a peltate expansion to which they were attached as he 

 supposes. 



As already indicated, the sporangia are located on elevated 

 longitudinal rows, which I regard as the equivalents of the 

 furrows on the stem. But it must also be noted that the 

 sporangia of contiguous rows stand opposite to each other. 



From this comparison of the structure of the fruit, foliage, 

 and stem of Pothocites with undoubted fruiting specimens of 

 Bornia radiata, their agreement is so complete that it appears 

 to me this genus can only be regarded as the fruit of Bornia 

 (Archceocalamites) radiata y Brongn., or of a closely allied 

 species of the same genus. 



In the short description which I originally gave of the 

 specimen collected by Mr. T. Stock at Glencartholm, it was 

 provisionally named Pothocites calamitoides. I have since 

 compared it carefully with the original type, and now find that 

 the points I regarded as of specific value cannot be retained 

 as such. 



The chief character which induced me to bestow a specific 

 name upon this specimen was the much greater breadth of 

 the segments in proportion to their length, when compared 

 with Pothocites Grantonii. 



But this diversity is fully explained when we take into 

 consideration the different states of development in which the 

 two specimens occur. 



In P. Grantonii the fruit appears to have passed maturity 

 and shed all its spores, as indicated by the split sporangia, 

 whereas in the Glencartholm example the lowest segment 

 alone appears to have attained to this degree of ripeness, a3 

 only on it the u stellate " sporangia are shown. 



