PUNICULINA QUADEANGULARIS. 19 



been ablo to determine. Later on each egg becomes invested by a 

 second outer capsule, which is much thicker than the first, is clearly 

 derived from the eudoderm cells surrounding the ovum, and contains 

 numerous minute pigment granules very similar in appearance to 

 those in the endoderm of the stomach. This outer capsule has its 

 surface, in the fully-developed egg, raised into a series of low ridges, 

 forming an irregular surface pattern. 



Each egg has from its earliest appearance a very large and 

 conspicuous mtcleus or germinal vesicle, containing one and sometimes 

 two nucleoli or germinal spots. The germinal vesicle, which increases 

 greatly in size with the growth of the egg, consists of a tough, elastic, 

 and fairly thick membrane, with clear, apparently fluid, contents : it 

 lies adjacent to the stalk of attachment of the egg, and in many cases 

 projects into this stalk for a short distance. The nucleolus is spherical, 

 of a yellowish colour, aud distinctly granular. 



The average diameter of the mature eggs is 0-014iu.,andthe thickness 

 of the capsule 0-001 in. : while the germinal vesicle, which is usually 

 oval, measures 0-003 in. by 0-002 in. 



Whether fertilisation aud the early stages of development are, as 

 is most probable, effected within the body-cavity of the parent we 

 have had no opportunity of determining. In no case have the eggs in 

 our specimens commenced to develope ; indeed the germinal vesicle 

 is still present and unaltered in every one of the eggs we have 

 examined. 



We have not observed a micropyle, though from the thickness and 

 toughness of the egg capsule it is not improbable that one exists. 



Eggs sometimes occur within the coenenchymal canals, as is shown 

 in the lower part of Fig. 10. The eggs so found are usually either 

 fully developed ones, or else eggs that are very nearly mature. As we 

 have noticed several instances of this we are inclined to view it as a 

 normal condition, though how the eggs get into the canals, whose 

 diameter is much smaller than that of the mature eggs, and still more 

 how they get out again, is far from obvious. It may be that the eggs 

 are accidently dislodged when young and carried with the nutrient 

 matter into the canals, where they remain, and, receiving a plentiful 

 supply of food, grow. 



Besides the sexual process of reproduction there can V)e but little 

 doubt that Funicidina can multiply asexually by gemmation or budding ; 

 this asexual process serving, as in other colonial Calenterata, to 

 increase the number of individuals in the colony, whilst it is by the 

 sexual process alone that new colonies can be started. 



5. Anatomy of the Zooids. — 



The only important points in which the zooids differ from the 

 polypes are the following : — 



1. They have no tentacles, and no distinct calyx. 



2. They have only two mesenterial filaments, viz., those corres- 

 ponding to the two long filaments of the polypes : like thcbe latter they 



