274 Proceedings of the Royal Physical Society, 
renberg was doubtless right in considering this animal vivi- 
parous ; but it remains to be determined whether the young 
are produced by gemmation or ovulation. In Spirillina 
foliacea I have found the highly refractive bodies I have 
above described as " primitive ova." 
Explanation of Plate IX. 
Fig. 6. Specimen of Truncatulina, decalcified ; a, membranoiis basis of sliell ; 
b, sarcode; c, ovum, with germinal vesicle and spot; c?, segment or 
zooid destitute of ovum. 
2. On the Reproduction of Ophrjodendron. 
Ophryodendron ahietinum, which 1 have figured in various 
attitudes in PL X., has been noticed elsewhere by Claparede 
and Lachmann* and myself t several years since; but it 
was not until the spring of the present year that I was able 
to discover its mode of reproduction. The animal presents 
the appearance of an oblong sac filled with homogeneous 
and finely molecular matter, and is found attached to the 
corallum of Sertularia pumila. From one end of the body 
or sac arises a proboscis, generally appearing as a short and 
closely-wrinkled club, but capable of being produced to a 
remarkable distance as a glassy ribbon surmounted by 
numerous twining tentacles. The sac usually shows no 
trace of a nucleus or contractile vesicle, nor are its contents 
differentiated into an external and internal tissue (ectosarc 
and endosarc), as in Actinophrys and others of the class 
(" Acinetiens") into which it has been introduced. The 
structure of the proboscis differs from that of the sac in the 
development within it, of a clear and highly refractive tissue, 
corresponding to the muscular element in the branches of 
Zoothamnium, and in the more directly contractile pedicle 
of Zooteirea. In the proboscis of Ophryodendron, as in the 
body of Epistylis, the contraction of the muscle throws its 
outer covering into close folds. The tentacles are formed 
of a continuation of the contractile tissue of the proboscis, 
and are covered to within a short distance of their tips by 
the integument. The proboscis, when extended, hangs 
* Etudes sur les Infusoires et les Ehizopodes, par Edouard Claparede et 
Johannes Lachmann. 
t Edin. Phil. Journal, July 1859. 
