838 DR. G. J. HINDE ON RECEPTACULITID®. 
Iscuaprres Murcuisonii, Kichwald, sp. 
1842, Tettragonis Murchisonit, Kichw. Urwelt Russlands, Heft 2, 
Dr Clots ds taller 
1842. Zamia rossica, Kutorga, Verhandl. d. min. Gesellsch. St. 
Petersb. p. 7, t. 2. f. 3 a-c. 
1860. Zetragonis Murchison, Kichw. Leth. Rossica, p. 481. 
1860. Ischadites altaicus, Kichw. id. p. 487, t. 27. f. 4. 
1875. Tetragonis Murchison, Giimb. Beitr. p. 40, 45. 
1878. TLetragonis Murchisonii, Quenst. Petref. Deutsch. Bd. 5, 
. 592. 
: 1880. Tetragonis Murchison, F. Romer, Leth. Pal. Th. 1, 
p. 3038. 
The typical example of this species is elongated pear-shaped ; it 
measures 100 millim. in length, by 58 millim. in width. The baseis 
stated to have a short stem, but this is probably incorrect, as none is 
shown in the figure, which is slightly concave below; and as the 
author also says that the basal portion is broken off there seems to be 
no proof of his asserted stem. The specimen is widest at its lower 
third, and gradually tapers to the summit, which is curved. The 
typical example only shows the vertical and concentric lines formed 
by the horizontal spicular rays, and the perforations of the vertical 
rays. 
nes rossica, Kutorga (Ischadites altaicus, Kichw.), appears to 
me from the figures and description of the author to be not im- 
probably a specimen of J. Murchisonu, in which the summit-plates 
of the spicules have been preserved. The specimens figured do not 
show the characters either of the base or summit. The spicular 
plates are rhomboidal in the figure, though some are stated to be 
hexagonal; they vary from 3°5 to 7 millim. in width, and clearly 
show concentric lines of growth. In a section of a small indi- 
vidual there are vertical spicular rays 10 millim. in length. By 
Kutorga the form was referred to a pine-cone. 
Distribution. Orthoceratite limestone: Reval, Wesenberg, Baltic 
Provinces of Russia. 
TETRAGONIS SULCATA et PARVIPORA, Hichw. Lethea Rossica, pp. 482, 
433, Atlas, t. 27. f. 5, 6. 
These two species are, as already remarked by F. Romer, of an 
altogether different character from the type of the genus, and do 
not belong to the family. 
Trerragonis Dansyi, McCoy, Brit. Pal. Foss. p. 62, t. 1p. f. 7, 8. 
TETRAGONIS EIFELIENSIS, F. Romer, Leth. Pal. Th. 1, p. 304, 
f. 5, 6. , 
These species are also of a different character from JIschadhites 
Murchisonii, and belong to the genus Dictyophyton, Hall. 
