CAMPTOPLITES 443 



1. Camptoplites bicornis (Busk). 



Bitgula bicornis Busk, 1884, p. 40, pi. ix, fig. 1 a-e; Kluge, 1914, p. 622, text-fig. 7 d-f. 



Camptoplites bicornis Harmer, 1923, p. 300. 

 Station distribution. Not represented in the Discovery collections. 

 Geographical distribution. Southern Ocean, 53 55' S, 108 35' E, 3568 m. (Busk). 



Secondary branches are not to be found in the type specimens of Camptoplites 

 bicornis (87. 12.9. 196, 197; 99. 7.1. 271, 1013) which are fragmentary, and they are 

 not shown by Busk. They might nevertheless be present in complete colonies. All three 

 types of avicularia are present, as shown in the figures of Busk and Kluge (whose 

 figures of the avicularia were drawn from one of Busk's preparations). 



The varieties of Camptoplites bicornis 



The Discovery collections include the three forms treated by Kluge as varieties of 

 C. bicornis, and one, C. bicornis var. qiiadriavicularis, hitherto undescribed. The specimens 

 of var. magna belong to forma elongata, forma ventricosa not being represented. 



Kluge 's varieties are clearly recognizable from his descriptions although there are 

 discrepancies in the explanation of pi. xxix in which the main and secondary branches 

 of var. compacta and var. elatior purport to be represented in four separate figures. 



Fig. 1, described as a main branch of var. compacta, appears to represent two secon- 

 dary branches with two zooecia of a main branch. It resembles the less compact speci- 

 mens of var. compacta which is somewhat variable in the character from which it gets its 

 name. Fig. 2 shows very compact secondary branches of the same variety. 



Figs. 3 and 4, described as main and secondary branches respectively of var. elatior, 

 both show main branches with small secondary branches. They clearly represent distinct 

 varieties and, as they show all the main features of var. magna (which is not otherwise 

 figured) and var. elatior, it seems likely that the plate was intended to show the main 

 features of all three varieties and that a mistake was made in compiling the explanation. 

 Unfortunately, the magnification of the figures is not given, so that a comparison of 

 absolute dimensions cannot be made. The large long-headed avicularia in fig. 3 have a 

 slightly more acute upper head-angle than any in Kluge 's range for var. magna form 

 elongata (115 as compared with 133-160 ), but agree with the smallest avicularia found 

 in my material of var. magna. 



The little points on each side of the terminal point of the mandible of the round- 

 headed avicularia (Fig. 43 N), which were figured by Kluge (fig. gc, p. 623) in var. 

 elatior and mentioned in his description of var. magna can be found in both varieties. 



In addition to the differences noted by Kluge, the varieties appear to be distinguished 

 by their ovicells. The ovicell of var. compacta was well figured by Kluge (text-fig. yc). 

 The proximal expansion shown in the figure is the base of the distal zooecium. Waters 

 (pi. i, fig. 40) also shows this ovicell quite well. It occupies less than two-thirds of the 

 width of the zooecium, the distal corners of which rise to a point on either side of it 

 (Fig. 44 C). At each side, where it joins the ovicell, the distal wall is thickened and 



