310 



seen in the whole colony seem to be in mutual connection with each other, often 

 by means of a narrow, tube-shaped prolongation, and through one or several of 

 these they seem as a rule to open out on the surface of the zocEcia. 



In the above-cited work Whitelegge puts forward the extremely peculiar 

 view, that in these forms in contrast to what is known in all other calcified 

 Bryozoa the new zocecia arise scattered amongst the fully developed and that the 

 chambers which are here called lunoecia are just such rudiments of new zooecia, 

 which according to the author may arise both in the oldest and youngest parts 

 of the colony. This view is however quite incorrect and is in complete conflict 

 with my investigations on these chambers. Further, it is readily seen that the 

 new zocecia in all members of this family are formed at the free margin, and 

 even the idea that new zooecia can be intercalated between the older in a well- 

 calcified Bryozoa colony is so improbable that I have no hesitation in declaring 

 such a process impossible. The improbability is further increased in that a number 

 of these species have a very regular form, which is conditioned just by a regular 

 mode of growth. Mac Gillivray* does not hesitate to accept Whi tele gge's sup- 

 position, but with the modification that new zooecia according to him arise also 

 between the marginal zooecia. In the species of the genus Conescharellina at the same 

 time as new zooecia arise on the margin of the colony, the inner cavity gradually be- 

 comes filled with small avicularia, which stand in connection with the zocecia and 

 with each other by means of small uniporous rosette-plates, and a longitudinal section 

 through such a colony shows them to be arranged in horizontal layers. The small 

 pore situated immediately distally to the aperture and which according to White- 

 legge is covered externally by a membrane, leads into a small cavity in the wall 

 of the zooecium, which sometimes projects on the inner surface. The ooecia, which 

 have hitherto only been found in Coneseharellina philippensis and C. cancellata 

 (PI. XXIII, figs. 8 a, 8 b), occur in the latter species in very small numbers and 

 usually in the neighbourhood of the free margin of the colony. Their outer aper- 

 ture leads into a space formed by the peristome, at the bottom of which is the 

 zooecial operculum. 



The rule in this family that all the other separating walls are single holds 

 true also for those separating the zocecia in the two opposite layers in two-layered 

 colonies. In these further the zooecia of the one layer extend in between those of 

 the opposite layer in such a manner, that a section through the thickness of the 

 colony shows the zooecia in the two layers to be separated by a zigzag line. 



How far the division of the genera proposed here is natural must be deter- 

 mined by investigation of a larger material, 



'■ 76, p. 88, 



