THE EXOGONE^. 24 1 



My preparations quite definitely contradict Pierantoni's account of the 

 early stages in one point. One set consists of a 4-celled stage in which the 

 cells are quite equal and symmetrical with the nuclei approximated towards 

 the animal pole evidently in preparation for the formation of the first four 

 micromeres, as in the other Exogonea; and in the Polychpeta in general. Later 

 stages observed also correspond quite closely with those of Exogone. 



Summary. 



The following are the most important of the results embodied in this 

 paper : — 



1. Descriptions and determinations of Australian species of Exogonecr. 



2. Demonstration of the role of the pedal glands in producing the secretion 

 by means of which the ova are attached after extrusion. 



3. Description of the proventriculus with its non-striated muscle-columns, 

 and of hitherto undescribed glands — the pro ventricular glands — the ducts of 

 which open into it. 



i. The following out of the changes undergone in Exogone by the nephridia 

 in both sexes associated with the development of the sexual elements. 



5. The hermaphrodite condition in Grubea jmsilloides. 



6. Description of stages of the development not previously investigated. 



Bibliography. 



1. Augeneh, II. — Polychffita I, Errantia. Die Fauna Siidwest-Australiens, Baud iv. 



Lief. 5. 1913." 



2. Claparede, R. — Annelides ebetopodes du Golfe de Naples. Mem. Snc. Phys. Hist. 



nat. Geneve, tome xix. 1868. 



3. Clapakede, R. — Beobaclitungen iiber Anat. und Entwickelungsgeschicbte wirbelloser 



Tuiere, etc. 1863. 



4. Claparede, B. — Glamires Zootomiques parmiles Annelides de Port-Vendres. Mem. 



Soc. Phys. Hist. nat. Geneve, tome xvii. 1864. 



5. Dujarthn, F. — Note sin- mi Aunelide {Exogone pusilla) qui porte a la ibis ses ceufs et 



ses spermatozoides. Ann. Sci. Nat. 3 serie, tome xv. 1851. 



6. DuPlessis, G. — Un cas de protandrie cbez les Syllidiens. Rev. Suisse Zool. vol. xvi. 



pp. 321-328 ; pi. 10. 1908.* 



7. Ehlers, E. — Die Borsten-wiirmer. 1864. 



8. Ehlers, E. — Polychasta der Hamburg. Magalbaens. Sammelreise. 1897. 



9. Ehlers, E. — Die Polycbreten. Sammlung der deutscben Siidpolar Exped. 1901-1903. 



1913. 



Only linown to me tbrough tbe account given by Tolls (29). 



