368 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
This genus is purely zoarial. The articulation is only an adaptation to some 
special circumstances, particularly to life on large marine algae whose mobility 
is very great. It is therefore not astonishing to note some apertures of different 
form. On the other hand, the characters of adaptation can very well become fixed 
in general descent and transform themselves into essential characters One must 
not forget that the bryozoan individual is the zoarium issued directly from the 
larva, and not the zooecium, which is only a bud of the aforesaid larva. 
In the present case our knowledge of the ovicells and the operculum is of little 
importance. It is better, therefore, to admit the genus such as Tenison-Woods 
has conceived it. 
The genus still exists in the waters off the coast of Florida, which is still 
another proof in favor of the continuity of the faunas in the Gulf of Mexico. 
TETRAPLARIA TUBERCULATA, new species. 
Plate 48, figs. 7-10. 
Description . — The zoarium is articulated, the segments are composed of a 
dozen zooecia placed back to back, disposed in four series, placed two by two at 
right angles. The zooecia are little distinct, elongated, subcylindrical ; the frontal 
is convex and formed of a tremocyst with small pores. The aperture is semilunar; 
the proximal border is somewhat concave and bears a triangular rimule. On each 
margin of the aperture there are two large symmetrical tubercles. 
Measurements . — Zooecia 
Lz= 0.12 mm. 
/.3=0.11 mm. 
Affinities . — In the distinctly schizoporelloid form of its aperture this species 
resembles very much Tetraplaria australis Tenison-Woods, 1878. 1 It differs 
in its nonoblique aperture and the presence of two oral tubercles. 
Occurrence . — Upper Jacksonian (Ocala limestone) : Chipola River, east of 
Marianna, Florida (rare). 
Cotypes. — Cat. No. 64070, U.S.N.M. 
TETRAPLARIA CAUDIFERA, new species. 
Plate 48, figs. 11-14 
Description . — The zoarium is articulated ; the segments are formed of four longi- 
tudinal rows of alternate zooecia, placed at right angles. The zooecia are distinct, 
very elongated, narrowed in the back in the form of a tail ; the frontal is convex 
and formed of an incomplete tremocyst surrounding a sort of smooth plastron. 
The aperture is elongated, elliptical, bearing two small, lateral denticles; there is 
a small vestibular arch. On each side of the aperture there are two small, very 
simple avicularia without denticle or pivot. 
Measurements . — Apertures 
ha= 0.19 mm. 
la= 0.13 mm. 
Zooecia 
Lz= 1.3-1. 5 mm. 
/2=0.40 mm. 
1 It is to be noted that the figure given by Tenison-Woods 1878, resembles but little the figure of 
MacGillivrav, 1895. The first is smooth with a lepralioid aperture ; the second is punctate with a schizo- 
porelloid aperture. 
