Lycopodiaceons Cones from the Lower Coal Measures. 383 
arranged in rows, somewhat recalling the arrangement of the cells of the 
prosenchymatous sporangial wall of Spencerites. 
The spores themselves are not definitely preserved in any sporangium 
but two brown masses of ill-preserved material in the lowest section of the 
series may represent decayed masses of microspores. 
The cone which has been described above differs from all other described 
Lycopodiaceous cones in the manner of attachment of the sporangia. In 
its general characters it much resembles Lepidostrobus , and I think is 
undoubtedly a member of the Lepidodendraceae ; at the same time the dis- 
tinctly different insertion of the sporangium entitles it to generic distinction, 
and I beg to propose for it the name of Mesostrobus Scottii , in commemora- 
tion of Dr. D. H. Scott’s connexion with the three most interesting known 
Lycopod cones, Spencerites, Lepidocarpon, and Miadesmia. 
The genus Mesostrobus may be defined as follows : — 
Lycopodiaceous cones resembling Lepidostrobus in all characters except 
in having the sporangium only attached to the distal portion of the horizontal 
portion of the sporophyll. 
This diagnosis is to be regarded as provisional ; it is possible, for 
example, that the insertion of the ligule in a deep pit may turn out to be of 
generic value if further species are found. 
Any general discussion of the inter-relationships of the Lycopodiaceous 
cones has to consider especially the following types: — Bothrodendron mun- 
duin , Lepidostrobus , Lepidocarpon , Miadesmia , Lycopodium , Selaginella , 
Spencerites , and the cone just described. 
I propose to discuss primarily the relationships of Lepidostrobus. This 
shows itself a highly specialized genus in the great radial extension of the 
sporophylls. It appears highly unlikely that the primitive Lepidodendroid 
had this character, and I believe its cone to be nearly represented morpho- 
logically by that of Bothrodendron mundum and the male Miadesmia. 
Two cones have now been attributed to Bothrodendron ; the small cone 
of B. mundum — (?) A. punctatum, and Bothrostrobus Olryi , Zeiller, which was 
found by Mr. Kidston, attached to a twig of Bothrodendron minutifolium , 
Boulay. This latter cone is exactly like Lepidostrobus , except that its sporo- 
phylls are in verticils, and are relatively short. 
Bothrodendron is one of the most ancient genera of the Lycopodiales. 
In the upper Old Red Sandstone of Kiltorkan two species occur. Bothro- 
dendron kiltorkense and the plant described as Knorria or Sagenaria 
Bailyana ; this last plant, as I have determined from the examination of a 
specimen in the Manchester Museum, is undoubtedly a Bothrodendron , 
although of a rather curious type. 
The same plants occur in the Ursa flora of Bear Island, with 
B. Wilkianum in addition. 
The only Lycopodiaceous fructification known from Kiltorkan is 
