218 PROF. F. E. WEISS ON A BISERIATE HALONIAL 
outer cortex forms the boundary, with small elevations of tissue in connection with 
the leaf-trace bundles. The relative position of these is such that on connecting the 
two nearest lateral ones the distance between them is almost equal to that between two 
standing vertically one above the other. 
The internal structure will be described in detail in a later portion of this paper; so 
that it will be sufficient to say here that it agrees very closely with that described by 
Williamson for Lepidodendron fuliginosum (Lepidophloios fuliginosus)—a fact already 
stated by Dr. Scott (1898) and Mr. Lomax (1899). 
In his communication to Section K at the Bristol Meeting of the British Association, 
Dr. Scott mentioned this agreement in structure, and regarded this halonial specimen 
as probably belonging to Lepidodendron fuliginosum. 
At the meeting of the British Association at Leeds, however, in 1890, Messrs. W. Cash 
and James Lomax (1890) had shown that a fossil revealing undoubtedly similar internal 
structure to that of Lepidodendron fuliginosum of Williamson had the typical transversely 
elongated leaf-scars of Lepidophloios. Hence they suggested the name of Lepidophloios 
fuliginosus for the stem previously described by Williamson. Williamson, however, 
in. Part xix. of his Memoirs on the Organization of the Fossil Plants of the Coal- 
Measures, which appeared three years later, 1893, still retained the name of Lepidodendron 
JSuliginoswn for the fossil described by himself, and probably did not sufficiently appreciate 
the separation of the two genera, for ina note to a “ Correction of an Error of Observation 
in Part xix. &c." in 1894, he states: “It appears to me that much uncertainty exists 
among palzobotanists respecting the structures that distinguish Lepidodendron from 
_Lepidophloios”’ *. 
It is probably due to the retention of the name Lepidodendron fuliginosum by 
Williamson after the publication of Messrs. Cash and Lomax’s note, that their observation 
did not receive its full recognition for some time and that the name Lepidodendron 
Suliginosum was retained for so long. 
Mr. Kidston (1893), however, in his memoir on Lepidophloios and on the British species 
of the genus, had duly recorded the observation of Messrs. Cash and Lomax, and after an 
examination of their specimen was inclined to identify it with Lepidophloios acerosus. 
An examination of the transverse sections of the specimen described by Cash and 
Lomax (1890) in the Cash Collection, now in the Manchester Museum, has convinced me 
of the identity in structure of this Lepidophloios with that of Williamson’s Lepidodendron 
fuliginosum, and also with the internal structure of the halonial branch forming the 
subject-matter of the present investigation. 
Having identified the halonial branch now under consideration with Lepidophloios 
| fuliginosus on the strength of its internal structure, the next and probably the greatest 
| point of interest attaches to the fact that, if the identification is correct, we have in this 
. instance an halonial branch of Lepidophloios with two vertical rows of tubercles, instead 
of the spiral arrangement of tubercles usually considered typical of the fruiting- 
` branches of Lepidophloios. Indeed, according to some definitions of Halonia, our 
* Proceedings of the Royal Society, vol. lv. (1394) p. 423, note. 
