308 



PHILOSOPHICAL NOTES ON 



structure are tubes, " in two series, differing slightly in size, and 

 they open on the surface by apertures correspondingly different in 

 dimensions, of which the larger ones are called the * gastropores ' 

 (a), and the smaller * dactylopores ' (6), Fig. 131. The gastro- 

 pores and dactylopores may be irregularly distributed, or the 

 dactylopores (the smaller ones) may be arranged in more or less 

 deiinite systems roimd the gastropores." In the tubes are lodged 

 zooids. Their reproductive process is imperfectly known. 



Fig. 131. Millipora alcicomis ("Manual of Palaeontology," Nicholson 

 and Lydekker, pi. 108) : (^) natural size, (^) part of surface enlarged. 



D 



Fig. 132. (C) portion of Lemon leaf, showing large oil-cells surrounded 

 by smaller ones : (Z>) is a longitudinal section of Lemon peel, showing the 

 same disposition of oil-cells (" Cultiv. Oranges and Lemons of India," pi. 181a 

 and pi. 188e)- 



