CAMPTOPLITES 445 



Key to the varieties of Camptoplites bicornis in the present collections 



1. Small long-headed avicularia with thickening where beak joins head (as in Bugula), round- 



headed avicularia usually of two sizes ...5. var. quadriavicularis 



Avicularia without thickening where beak joins head, round-headed avicularia all of one 



size ... ... ... ... ... ... ... ... ... ... ... ... 2 



2. Ovicell occupying less than two-thirds of width of zooecium, large long-headed avicularia 



relatively small, fairly uniform in size, their upper head-angle less than 100° 



...2. var. compacta 

 Ovicell occupying more than two-thirds of width of zooecium, large long-headed avicularia 



variable in size mostly relatively large, their upper head-angle at least 1 1 5 , usually more 3 



3. Zooecia tapering proximally fairly gradually, zooecia of main branches considerably longer 



than those of secondary branches, distal corners not conspicuously pointed 



3. var. magna 

 Zooecia narrowing rather suddenly at beginning of tubular part, zooecia of main branches 

 not markedly different from those of secondary branches, distal corners drawn out into 

 almost spine-like points ... ... ... ... ... ... ... 4. var. elatior 



2. Camptoplites bicornis var. compacta (Kluge). Plates X, fig. 1, XI, fig. 1 ; Figs. 43 M, 



44 C 



Bugula bicornis var. compacta Kluge, 1914, p. 619, pi. xxix, figs. 1, 2, text-figs. 7 a-c, 8 (not 

 text-fig. 7 d-f, see C. bicornis). 



Station distribution. Antarctic: Weddell Quadrant, St. 187; Victoria Quadrant, Sts. 1652, 1660. 



Geographical distribution. Palmer Archipelago (Discovery); Bellingshausen Sea; Wilhelm II 

 Land (Kluge); Ross Sea (National Antarctic Expedition; Terra Nova; Discovery). 



The varieties of Camptoplites bicornis are compared on p. 443. 



The upper head-angle of the large long-headed avicularia of my material may be as 

 much as ioo° though it is usually nearer 8o°. 



Kluge (p. 622) explains that the avicularia in his text-fig. 7 were drawn from the type 

 specimen of C. bicornis and not from var. compacta. 



3. Camptoplites bicornis var. magna (Kluge). Plates X, fig. 2, XI, fig. 2; Figs. 44 E, 



45 A, B. 



Bugula bicornis var. magna form elongata Kluge, 1914, p. 623, text-fig. 10. 



Bugula bicornis var. elatior (part) Kluge, 1914, pi. xxix, fig. 3. 



Station distribution. Antarctic: Weddell Quadrant, Sts. 39, 164, 180, 187 and Deception 

 Island; Victoria Quadrant, Sts. 1652, 1660. 



Geographical distribution. South Georgia; South Orkney Islands; South Shetland Islands; 

 Palmer Archipelago (Discovery); Bellingshausen Sea; Wilhelm II Land (Kluge); Ross Sea (Terra 

 Nova; Discovery). 



The varieties of Camptoplites bicornis are compared on p. 443. 



The large long-headed avicularia of my material of var. magna are all of the type of 

 Kluge's form elongata. They correspond in size and general shape to the smaller avi- 

 cularia of the series figured by Kluge, but the smallest are even smaller. These smallest 

 ones approach those of var. compacta in size but have a more obtuse upper head-angle 



(«S°)- 



D XXII 19 



