DIASTOPORID^E. 15 
The collection of Mr. John M. Nickles contains an example of this species from the original 
Wenlock shales material studied by Mr. Vine. Fig. 10, PI. IV, represents several of the 
zooecia of this specimen enlarged, and a comparison of this figure with those of the American 
form shows that there can be little doubt of the specific identity of the two. This English 
specimen is labeled Stomatopora elongata in Mr. Vine's handwriting, so that there is no ques- 
tion of its authenticity. The long stoloniferous processes which Mr. Vine mentions as 
intermingling with the cells are the stolons of ctenostomatous bryozoa such as Vinella or 
Ascodictyon and have no connection at all with the Stomatopora. Such widely diverse 
incrusting species are often found with their zoana intermingled and but little care is usually 
required to determine that one is merely growing over the other. The following descrip- 
tion brings out the characters as observed by the writer: 
Zoarium incrusting foreign objects, the smooth cpitheoa of corals or bryozoa being most 
favored in the American examples. Zooecia uniserial, branching at irregular intervals, 
slender, fusiform, increasing slowly in size from a diameter of 0.03 to 0.04 mm. at the 
proximal end to one of 0.15 to 0.18 mm. at the distal or anterior end, which, although 
normally rounded, is sometimes slightly drawn out. An average zocecium is 0.60 mm. in 
length; when arranged in a straight line, seven zooecia may be counted in the space of 4 mm. 
Aperture small, rounded, subterminal, with a slightly elevated border and less than half 
the greatest width of the zocecium in diameter. Surface of the zooecia smooth, probably 
finely porous. 
Compared with other uniserial forms of Stomatopora, S. elongata resembles S. delicatnla 
James, which ranges through the Mohawkian and Cincinnatian groups, but the latter 
species has slightly longer and more slender zooecia. In all probability 5. elongata is the 
Silurian representative of the Ordovician S. dehcatula The very much larger and relatively 
shorter, transversely wrinkled zooecia of the associated Stomatopora dissimilis are so 
different that comparisons are scarcely necessary. 
The American form here identified as Stomatopora dissimilis is probably the same as 
Stomatopora parva Ringueberg, but the description and figures of the latter are so poor that 
without an examination of the type specimen the synonymy can not be determined with 
absolute certainty. In spite of this uncertainty, the writer has ventured to place Ringue- 
berg's species as a synonym on the strength of his original description, which, for the sake 
of comparison, is quoted below: 
Adnate, minute, irregularly branching. Cells uniserial subcylindrical, not inflated, somewhat 
variable in length, some being a third shorter than the average. Calice slightly elevated. This 
species is about one-third as large as S. recta and is readily recognized by its minute size and straignt 
cells. (From the Niagara shales at Lockpori N. Y ) 
Occurrence. — Buildwas beds, Wenlock shales, Shropshire, England; Clinton formation, 
Sevenmile Creek, near Eaton, Ohio; Rochester shale, Rochester and Lockport, N. Y., Wal~ 
dron shale, Newsom, Tenn 
Catalogue number, 35475, U. S. National Museum. 
Stomatopora dissimilis Vine. 
PI. IV. figs. 15-19. 
Stomatopora dissimilis Vine, Quart. Jour. Geol. Soc. London XXXVII, 1881, pp. 615, 61f>, figs. 1-8; 
XXXV11I, 1882, p. 50. 
Stomatopora recta Ringueberg, Bull. Buffalo Soc. Nat. Hist., V, 1886 p. 20 pi. 2. figs. 15. 15a. 
Aulopora sp. Hall Nat. Hist. New York Pal. II, 1852. pi. 50. rigs 27, 29. 
Original description — Zoarium adnate, branching generally attached to stems of Crinoidea very 
rarely to broken snells; branches linear, sometimes wavy and anastomosing. Zooecia invariably 
uniserial, and, in the best preserved, very finely ribbed transversely; tbe oiai extremity slightly raised; 
orifice circular or subcircular. Ocecial ceils rather ventncose and strongly ribbed ('.'). Each normal 
zocecium about half a line, average about 6 to 3£ lines. 
A series of specimens from the Silurian rocks of various localities in Europe and America 
shows that the Wenlock shales species described by Vine as Stomatopora dissimilis has as 
