482 MR. A. W. WATERS ON 



Cate-YAria diaphana Bask. (PI. LXIV. figs. 6-11.) 



Scruparia diaphana Busk, Q. J. Micr. Sc. vol. viii. p. 281, 

 pi. xxxi. fig. 1 (1860). 



Catenaria diaphana Busk, " Polyzoa," Zool. Ohall. Exp. vol. x. 

 pt. xxx. p. 14, pi. ii. fig. 3 (1884). 



Halysis diaphana Norman, " Polyzoa, from Madeira," Journ. 

 Linn. Soc," Zool. vol. xxx. p. 296 (1909) ; Levinsen, Morph. & 

 Sjst. Studies on Cheil. Bryozoa, p. 274 (1909). 



The ovicell has not before been described, in fact Levinsen says 

 it is Avanting. A growth of the outer calcareous wall of this recum- 

 bent ovicell projects forward from the distal end in the middle 

 and also from the sides, forming at first one elongate space which 

 is subsequently divided, making two vacant spaces or laige pores. 

 The node with an ovicell or ovicells is never a single zooscium, 

 and there are often many zooecia with ovicells in a node (fig. 9) ; 

 six together have been counted many times. We have seen 

 many ovicelligerous zooecia in a node in Catenicellidge. The node 

 may, however, be only one ovicelligerous zocecium follow*ed by an 

 ordinary zooecium. As a rule, from the distal end of the older 

 zooecium a new zocecium arises in the median line, and there 

 may also be one growing laterally from very near the end, or 

 occasionally one on each side. 



The front wall is but little raised and is perforated, the per- 

 forated part being bounded on each side by a raised ridge, and on 

 the dorsal surface there are two lines of pores. The parietal 

 muscles start under the longitudinal ridge. The operculum has 

 a dark mark in the proximal part (fig. 8), and there are 20-22 

 tentacles. There are radicles attached to the side of the zooecium, 

 with the attachment elongate in the direction of the long axis. 

 None of the ovaria seen in sections are surrounded by the 

 follicular cells occurring in nearly all species. The ovarium 

 (fig. 10), with many ovarian cells, is found near the basal wall, 

 a short distance below the ovicell. The ovum is seen in the 

 upper part of the zooecium, where there are strong muscles ready 

 to force it into the ovicell from below internally, and sometimes 

 there is an embryo or ovum in the ovicell as well as a large ovum 

 below in the zooecium. Levinsen * considers that in some species 

 of Bryozoa the ovum comes out of the zooecium and then enteis 

 tlie ovicell, but until proof is brought forward we may hold a 

 position of doubt, as the contrary is known in so many cases. 



All the characters given by Norman for his genus Halysis 

 apply to Catenaria lafontii Aud., and it is not clear that a new 

 o-eniis is required. Levinsen ijiakes the absence of the avicularia 

 aird of ovicells a reason for separating this species from his genus 

 Savignyella = C .lafontii K\x(\., but in a large proportion of genera 

 there is sometimes an avicularium, sometimes none. The genus 

 Catenaria was discussed in my Report on the Sudanese Biyozoa t. 



* Lnc. cit. p 67. 



t Jouni. Linn. Soc, Zool. vol. yxxi. pp. 130, 131 (1909). 



