366 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
branchial cavity (the brood pouch) develops to receive them. The 
oviduct extends into this nearly to the closed distal end. Apparently 
the pouch (and the section of the oviduct contained in it) increase in 
length only so fast as there is need of space to contain more embryos. 
The youngest embryos are therefore in the distal part, and there is a 
series of older and older embryos and larvae extending back to the 
proximal end of the pouch. Owing to the narrow neck connecting 
the pouch with the peribranchial cavity of the zooid, the larvae cannot 
pass back into that cavity, but must escape by breaking through the 
wall of the pouch and the surrounding test. 
Holozoa clavata (Sars). 
Text-figs. 6, 7. 
1851. Leptoclinum davatum Sars, Nyt Mag. Naturvidensk., vol. 6, p. 154. 
1859. LeptocUnum davatum Sars, Forh. Videnskab-s-Selsk. Christiania, p. 66. 
1892. Distoma (?) sp., Herdman, Proc. and Trans. Liverpool Biol. Soc, 
vol. 6, p. 92. 
1896. DistapUa darata Huitfeldt-Kaas, Norske Nordhavs-Exp., Zool., vol. 
23, no. 1, p. 10, pi. 1, fig. 3. 
1903. DistapUa davata Hartmeyer, in Romer and Schaudinn, Fauna Arctica, 
vol. 3, p. 313, pi. 6, fig. 4; pi. 11, fig. 21. 
1904. DistapUa davata Hartmeyer, Wiss. Meeresunters., Abt. Helgoland, 
vol. 5, pt. 2. 
1905. DistapUa davata Bjerkan, Bergens Mus. Aarbog, no. 5, p. 16, pi. 3, 
fig. 1-3. 
1907. DistapUa davata Redikorzew, Ann. Mus. Zool. Acad. Sci. St. Peters- 
bourg, vol. 11, pp. 151, 154. 
1908. DistapUa davata Redikorzew, Trav. Soc. Nat. St. Petersbourg, vol. 39, 
pp. 20, 33. 
1908. DistapUa davata Bjerkan, Tromsoe Mus. Aarsheft., no. 25, pp. 87, 115. 
1909. Holozna davata Hartmeyer, Bronn's Tier-reich, vol. 3, suppl., p. 1437. 
Though varying nuich in shape, well developed colonies of this 
animal generally have a club-shaped, capitate, or acorn-like form, 
and are usually raised on a well marked peduncle which expands at its 
lower end into a broad base by which it adheres. Sometimes a colony 
may consist of more than one head (text-fig. 6) . Young colonies are 
simple small rounded masses attached by a narrow base. The zooids 
are confined to the heads, and systems and common cloacal apertures, 
if present, are hard to demonstrate. Sometimes a tendency of the 
zooids to be arranged in rows seems apparent, but on the other hand 
the fact that the zooids often project slightly above the general surface 
