186 CTENOPHOR^. Part II. 



the earlier stages of their growth, and the later development of those peculiarities 

 which distinguish the Lobatte as a sub-order. Indeed, the facts already ascertained 

 respecting the embryonic growth of the Ctenophoraj seem to jvistify the inference, 

 that while the Eurystomce are the lowest, the Lobato3 are the highest, and the 

 other sub-orders occupy an iutermediafe position between them ; for the promi- 

 nence of the anterior and posterior spheromeres over the lateral pairs and their 

 lobe-like prolongation in the Lobataj are characters not observed in the earliest 

 stages of their development, and marking therefore a progress which, not being 

 reached by the other sub-orders, assigns the highest position to the Lobata^. Again, 

 the amplitude of the coeliac cavity and of the chymiferous tubes in the very young 

 Lobatie coincides with the essential character of the Eurystoma?. So that, if the 

 develoj)ment of Cestum should not interfere, it would be natural to arrange the 

 Ctenophora) in the following order : Eurystomte, Saccatas, Ta^niatse, and Lobatse. 



