Geological Society of London. 421 



the appearance of elongated flattened stems, about one incli wide 

 on the average, sometimes represented only by casts, sometimes by 

 black carbonaceous films. They are ornamented with a series of 

 pucker-like depressions when seen from the interior, or with a 

 number of wart-like eminences when viewed externally. The latter 

 are the scars of the points of issue of the vascular bundles passing to 

 the leaves. Along the margins are seen spines or thorn-like projec- 

 tions, which may be the leaves or their bases ; these are apparently 

 arranged in spiral rows. Some stems appear to show dichotomous 

 branching. The authors discuss the relationships of these remains 

 with other described Devonian forms, and regard them as most 

 nearly allied to Psilophyton princeps, Dawson. They describe the 

 plant with doubt as a species of PsilopJiyton. 



6. " On an adherent Form of Productus and a small Spiriferina 

 from the Lower Carboniferous Limestone Group of the East of 

 Scotland." By K. Etheridge, Jun., Esq., F.G.S., of the Geological 

 Survey of Scotland. 



The author commenced by summarizing the different views that 

 have been expressed by writers as to the mode of life of the Pro- 

 ducti, and the function to be ascribed to the spines with which their 

 shells are furnished, in order to show the uncertainty that prevails 

 upon these points. He then described specimens of a small Pro- 

 ductus, found attached to encrinite stems and fragments of Polyzoa, 

 in the shale over the No- 2 Limestone of the Lower Carboni- 

 ferous Limestone group, chiefly in the neighbourhood of Dunbar. 

 The shells are attached by having some of the spines of the ventral 

 valve wound tightly round the bodies to which they adhere, some- 

 times singly, sometimes in clusters, the number of spines implicated 

 in the adhesion varying from two to seven or more. The attach- 

 ment took place during the life of the Crinoid, as evinced by the 

 subsequent growth of the latter, leading in many cases to the more 

 or less complete imbedding of the Productus. From the considera- 

 tion of the characters presented by the more mature valves, the 

 author stated that the nearest affinity of this species of Productus 

 appears to be with P. WrigJitii, Dav., but that it shows peculiarities 

 allying it to P. longispinus, Sow., P. scahriculus, Mart., and P. un- 

 datus, Defr. He was not prepared to describe it as a distinct species, 

 but suggested for it the name of Productus complectens, in allusion to 

 its embracing habit, in case of its proving to be distinct. 



The Spiriferina described by the author was compared by him 

 with S. cristata, Schl., var. octoplicata, Sow., and with S. inscidpta, 

 Phill., from both of which it differs in certain characters ; but as 

 only one specimen has been met with, he refrained fi-om founding a 

 new species upon it. The specimen is from FuUarton Quarry, near 

 Temple, Edinburghshire. 



7. " Notice of the Occurrence of Eemains of a British Fossil Z^ug- 

 lodon (Z. WanMyni, Seeley) in the Barton Clay of the Hampshire 

 Coast." By Harry Govier Seeley, Esq., F.L.S., F.G.S., Professor of 

 Physical Geography in the Bedford College, London. 



In this paper the author described the remains of a species of 



