THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 



No. 80. AUGUST 1874. 



XIII. — On the Nature of the Seed-like Body of Spongilla<; 

 on the Origin or Mother Cell of the Spicule ; and on the 

 Presence of Spermatozoa in the Spongida. By H. J. 

 Carter, F.R.S. &c. 



[Plate X.] 



Ever since 1849, when my figure of the development of 

 Spongilla from the seed-like body was published (' Annals,' 

 September 1849, vol. iv. pi. iv. fig. 2), I have been uncertain 

 of the real nature of this body ; but lately, as I have been 

 studying the living Grantia compressa in its oviparous state, 

 light has been thrown on its nature which seems to show its 

 real import. 



By reference to the ' Annals ' (I. c. pi. iii. fig. 6), it will be 

 observed that the seed-like body is composed of a horny 

 globular case with a hiliform opening, the cavity of which case 

 is filled with spherical transparent cells, each of which again 

 is charged with a great number of minute capsular granules 

 that I have termed " ovules." 



As the contents of the seed-like body grow out into the 

 water from the hiliform opening, each spherical cell takes up its 

 place in the " intercellular substance " or sarcodal mass, which 

 appears at the same time to form the body of the young Spon- 

 gilla ; and all the " ovules " respectively become developed 

 into monociliated and unciliated, polymorphic, monad-like 

 organisms, which, in their aggregation, form a pavement layer 

 around the spherical cell. This is well shown in the figure 

 to which I have first alluded. 



Again, if the so-called ovules be forcibly pressed out into 

 Ann. & Mag. N. Hist. Ser. 4. Vol. xiv. 7 



