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, membranous basis of shell ; 



b, sarcode ; c, ovum, with germinal vesicle and spot ; <?, segment or 

 zooid destitute of ovum. 



2. On the Reproduction of Ophryodendron. 

 Ophryodendron abietinvm, which I have figured in various 

 attitudes in PL X., has been noticed elsewhere by Claparede 

 and Lachmann* and myself \ 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. 



