NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
453 
OCHETOSELLA ROBUSTA, new species. 
Plate 57, figs. 11-17. 
Description . — The zoarium is free, cylindrical, branching. The zooecia are 
large, elongated, cylindrical; the frontal is very convex: it is terminated distally 
by a salient and almost complete peristomie; it is formed of a tremocyst with very 
small pores. The oral mucro bears a trenched spiramen and avicularium; the 
jieristomice is very oblique; its outlines are undefined. The oral avicularium is 
round, simple and without pivot. 
Measurements. — Zooecia 
I Lz= 1.20-1. 30 mm. 
\ls= 0.65 mm. 
Variations. — The development of the calcification gives to the zooecia some 
quite variable aspects which it is impossible to analyze, but which figures 14 to 17 rep- 
resent sufficiently. Figure 12 represents a very curious case of an inversion of 
zooecia on the same branch. 
Affinities . — This species is always easy to distinguish from Ochetosella jack- 
sonica by its large branches and the absence of areolae. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (common); 
near Lenuds Ferry, South Carolina (rare). 
Cotypes.— Cat. No. 64122, TJ.S.N.M. 
Family SMITTINIDAE Levinsen, 1909. 
Anatomical bibliography. — 1S65, Smitt, Skandi tiaviens Hafs-bryozoer, Ofversigt Kongl. Vet- 
enskaps-Akademiens Forlmncllinger, vol. 22, pi. 3, figs. 9, 10, 11 : pi. 5. fig. 4.— 1892. AVaters, 
Observations on tbe Gland-like Bodies in tbe Bryozoa, Journal Linnean Society, London, 
Zoology, vol. 24, pi. 19, figs. 15, 16. — 1900. AA t aters, Bryozoa from Franz Joseph Land, pi. 10, 
figs. 8-17;' pi. 12, figs. 3, 4. — 1904. AVatees. Expedition Antarctic Beige, Bryozoa, pi. 4, 
figs. 1, 2. — 1909. AVaters. Reports on the Marine Biology of the Sudanese Red Sea. XIII. 
The Bryozoa, Journal Linnean Society, London, vol. 31, pi. 14, fig. 14; pi. 15, fig. 11. 
The OAucell which is hyperstomial and imbedded in the distal zooecia opens 
into the peristomie. The peristome is produced and channeled in front. The 
operculum is (not universally) very thin; the lower edge is straight or slightly 
curved inward and hardly separated from the ectocyst ; the muscular attachments 
are usually a ridge on the border. There are very small oral glands often partly 
attached to the tentacular sheath. Spines. 
This family is a very important one, but unfortunately our knowledge of the 
anatomy and embryology is too little to allow us to fix its exact limits. The de- 
velopment of the peristome is one of the essential characters; we continue to follow 
the same terminology as for the preceding families. The orifice of the peristome is 
the peristomice (secondary orifice of Hincks) ; it is irregular and its outlines are 
vague and undefined. The apertura is the zooecial orifice closed by the operculum; 
it is not always visible externally. The internal tube formed by the development 
of the peristome is the peristomie. 
The calcification functions as in other genera. Nevertheless, the. pleurocyst is 
a frequent occurrence, and the greater part of the time the two calcareous layers 
are separable. 
