ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 371 



vesicle is of some size. The spermatozoa, like tlie ova, are developed 

 im large masses, and, like them, pass into the spaces in the thoracic 

 parapodia. They are generally found aggregated, and separate 

 spermatozoa are but rarely detected ; they resemble in form those of 

 Magelona. The segmental organs are confined to the 5th and 6th 

 segments, and serve as efferent ducts for the genital products ; they 

 consist of an infundibular and a spherical portion, and the cilia are 

 confined to the former. The latter apparently serves as the secreting 

 organ of the matter by means of which the genital products become 

 attached. The external pore resembles that seen by Cosmovici in 

 Pectinaria. 



Exogone gemmifera.* — C. Viguier, after a brief account of the 

 work of Pagenstecher and others on this annelid, states that he has 

 frequently found both males and females in the sexual condition ; 

 some of these have, and some have not setae, so that the view of 

 Pagenstecher that the asetal forms are agamic, and the setose sexual 

 is not confirmed ; so, again, E. martinsi may or may not have long setae. 



The author enters into some detail with regard to the history of 

 this development, as this form has served as the basis of Pagenstecher's 

 doctrine of lateral buds ; such an exception to the general rule that 

 germination takes place in a longitudinal direction deserved recon- 

 sideration ; and the author proposes to deal fully with the matter in 

 a more extended memoir. 



Structure and Development of Phoronis.f — W. H. Caldwell, in 

 a preliminary note on this Gephyrean, points out that the epistome 

 lying in the short line between the mouth and anus is the persistent 

 pre-oral lobe of the larva, and that this line is the median dorsal line. 

 The ventral surface is produced into a foot, which constitutes the 

 main part of the animal. The central nervous system retains its 

 primitive epidermic condition, and concentrations take place round 

 the mouth to form a post-oral nerve-ring ; in front of this are situated 

 a pair of sense-organs, which may be spoken of as the " ciliat jd pits " ; 

 the protuberances in Bhahdopleura, figured by Sars, may be their 

 homologues. The body-cavity is divided by mesenteries into three 

 chambers, and there is, further, a septum which passes from the line 

 of the nerve-ring into the oesophagus. The genital pores of Kowa- 

 levsky are the external openings of a pair of nephridia, each of which 

 consists of a simple ciliated tube, the cell-walls of which are filled 

 with brown concretions. These tubes open into the posterior chamber 

 of the body-cavity. There is a closed system of blood-vessels, con- 

 taining nucleated red corpuscles, and the walls of all the vessels are 

 contractile. The sexes are united in the same individual, and the 

 generative products are formed from cells of the efferent blood-vessel 

 which runs in the left anterior chamber of the body-cavity, and the 

 generative cells, like the nerve-cord, are asymmetrically placed. 



* Comptes Eeudus, xcvi. (1883) pp. 729-31. 

 t Proc. Eoy. Soc, xxxiv. (1883) pp. 371-83, 



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