182 REPRESENTATION OF THE 



has but a temporary existence, and is known as the suspen- 

 sor ; that subsequently generated is the true embryo, which 

 in the course of development protrudes an extension down- 

 wards (the radicle), and one directed upwards (the plu- 

 mule). 



The particulars now referred to appear to be the essen- 

 tial points in the process, and there is undoubtedly a close 

 correspondence in them, between the two kinds of plants. 

 The differences, which at first appear so great, seem to be 

 reducible to the following : — 



1 . The shedding of the fem-spores before any of the cel- 

 lullar gTowths are formed — and, of course, before impreg- 

 nation — while the phanerogamic ovule continues in situ till 

 the embryo is matured. 



2. The development from the spore, in its primary ger- 

 mination, of an external cellular growth or prothallium, 

 which afterwards simulates a cotyledon — whereas generally 

 in the ovule no cellular body is formed distinct from the 

 common tissue of the nucleus. 



3. The formation of numerous archegonia in the sub- 

 stance of the prothallium, each with a germinal corpuscule 

 in its interior — whereas in the ovule there is normally but 

 one such capsule — viz., the embryo-sac. 



4. The fi^equent co-existence of spermatic capsules and 

 of archegonia in the Cryptogamia within the same prothal- 

 lium ; whereas in phanerogamic plants, the organs contain- 

 ing the corresponding elements — i.e., the anthers and 

 germens — are from the very first quite distinct structures. 



To estimate the importance of these diversities they ^^dll 

 require to be considered seriatim. 



That mentioned first — the premature dispersion of the 

 seed-like bodies — is certainly a very constant point, but it 

 cannot be held to be of a kind to destroy the general cor- 

 respondence of the course of phenomena in the two cases, 

 for it is evidently a phenomenon of the same nature as the 



