386 W. A. HASWELL 
with unicellular glands. The caeca are of essentially the same 
structure, with numerous unicellular glands which discharge 
their secretion into the lumina. A name is needed to designate 
the small but distinet part of the digestive canal from which 
the caeca are given off. The term oesophagus is in general 
use for a corresponding part in the Nereids ; but, whatever its 
claims, it seems inappropriate to a compact glandular chamber 
with a ciliated epithelium. I propose instead the term post- 
ventriculus as not imvolving any doubtful homologies 
and indicating simply position. 
Though the post-ventriculus, with the caeca, resembles the 
intestine in its ciliated epithelium, it differs from the latter in 
the presence of the very numerous and characteristic uni- 
eellular glands. It is also sharply constricted off from it, and 
the narrow aperture of communication between the two is 
guarded by a valve composed of folds of the intestinal epithe- 
lium which must prevent the passage of liquid forwards from 
the mtestine. 
LITERATURE. 
1. Benham, W. B.—‘‘ Notes on some New Zealand Polychaetes ”’, 
‘Trans. N.Z. Inst.’, vol. 47, 1914. 
2. Claparéde, R.—‘‘ Annélides chétopodes du Golfe de Naples”, “Mém. 
Soc. Phys. Hist. nat. Genéve ’, t. 19, 1868. 
3. Ehlers, E.—‘ Die Borstenwiirmer’. Leipzig, 1864. 
4. Kisig, H.—‘‘ Ueber das Vorkommen eines schwimmblasenahnlichen 
Organs bei Anneliden ”’, ‘ Mittheil. Zool. Stat. zu Neapel’, Il. Bd., 
1881. 
5. Haswell, W. A.—‘ On the structure of the so-called glandular ventricle 
of Syllis”’, ‘ Quart. Journ. Micro, Sci.’, N.S., vol. 26, 1886. 
“A comparative study of striated muscle ’’, ibid., vol. 30, 1889. 
“On the Exogoneae ”’, ‘ Journ. Linn. Soc. Zoology’, vol. 34, 1920. 
8. McIntosh, W. C.—‘A Monograph of the British Annelids’, vol. 2, 
part 1. Ray Society, 1908. 
9. Malaquin, A.—* Recherches sur les Syllidiens”’, “Mém. Soc. Sci. 
Lille ’, 1893. 
10. Quatrefages, A. De.—‘ Histoire naturelle des Annelés ’, 1865. 
11. Saint-Joseph, Baron de.—‘* Les Annélides polychétes des cdétes de 
Dinard ’’, ‘ Ann. sci. nat.’, 7° série, t. 1, 1887. 
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