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a cylindrical segment. In the cavity of every zocecium we may distinguish be- 

 tween a narrower proximal and' a much wider distal part, curving outwards to 

 the surface under a right or an obtuse angle (PI. VII, figs. 4 a, 4 f , PI. VIII, figs, 

 lb, 1 c, 2 b). While the distal broader part, which bears the aperture, reaches 

 the axis of the colony, the case is different with the narrower part which only 

 reaches the frontal end of a separating wall, that separates the broad ends of 

 two zooecia for a short distance, but these two zooecia are not situated in 

 two adjoining longitudinal rows, but in two longitudinal rows separated by a 

 third. The narrow proximal part of a zocecium, which has a triangular trans- 

 verse section (PI. VII, figs. 4 b, 4 c) and is closed proximally by the part 

 of the distal wall, which is furnished with rosette plates, does not join the 

 corresponding part of another zocecium but the broad part of the zooecia in the 

 two neighbouring rows, with which it is connected by a multiporous, in these 

 zooecia inwardly arched rosette-plate. Each zocecium has thus on either side 

 two multiporous rosette-plates, one arching inwards in the broad part, and one 

 arching outwards in the narrow part. As a transverse section shows, the broad 

 part of a zocecium is nearest the axis separated by a separating wall from the 

 broad part of another zocecium, further outwards from the narrow part of a 

 neighbouring zocecium, and nearest the frontal side from the ooecium of the same 

 zocecium. A longitudinal section of a joint has a different appearance according to 

 whether it is cut right through the axis or beside it, as in the latter case we 

 may see not only the cavities of the two zooecia, which have been mostly affected 

 by the sections, but also a number of smaller cavities which have arisen by the 

 intersection of the stellate, adjoining separating walls and lead into a number of 

 intermediate zooecia. This may easily be seen on imagining a section carried 

 through fig. 4 c on PI. VII. Time has not •permitted me to enter thoroughly into 

 the classification of this family. It may however be reasonable to suppose that 

 the large genus Cellularia may naturally be divided into several, possibly accord- 

 ing to differences partly in the chitinous ridges sun-ounding the aperture partly 

 in the tooth-like processes of the latter. A generic division based only on the 

 difference in form of colony, on the other hand, I cannot acknowledge as natural. 

 Of the species described in the work of d'Orbigny mentioned above the 

 following may, I think, be referred to this family: Eschara Bixa (PI. 668), E. 

 Artemis (PI. 667), Escharinella elegans (PI. 683), Escharella Argus (PI. 666), Eschari- 

 fora rhomboidalis (PI. 684) and E. crassa (PI. 684), of which the three last named 

 in contrast to the other members of this family have a smaller number of large 

 pores surrounded by a raised margin. W^hile none of these figures show any 

 teeth in the aperture, the latter according to Waters is in E. Argus furnished with 



