396 DISCOVERY REPORTS 



Avicularian angles. I have previously (Hastings, 1939, p. 332, text-figs. 275 B, C; 

 p. 336, text-figs. 276 B, C) used Kluge's method of comparing the shapes of the heads 

 of stalked avicularia by means of their upper and lower head-angles, but a definition 

 of the terms may be useful here. In Fig. 27 C the lines AB, BC, CD form the upper and 

 lower head-angles (BCD and ABC respectively) of the avicularia, as these terms are 

 used by Kluge. It will be seen that the direction of AB is determined by the positions 

 of two structural points (A and B), that BC is the tangent at B to the curve of the head, 

 and that CD is the tangent common to the curves of the top of the head and the top of 

 the beak. Where the tops of the head and beak form one continuous curve, with no 

 intervening concave or flat portion, only the lower head-angle can be defined. 



Bicellariella Levinsen, 1909 



I. Bicellariella sp. Fig. 27 A. 



Station distribution. Sub-Antarctic : Sub-Antarctic Ocean, St. WS 776. 



Geographical distribution. Patagonian Shelf (Discovery). 



A single fragment of a species of Bicellariella from St. WS 776 is worth recording, 

 as the genus is not otherwise known from the Falkland region. 



In the shape of its rather long zooecia, the large size of its avicularia, and their position 

 on the third, or distal, section of the zooecium, it may be compared to B. capensis 

 (O'Donoghue, 1924, p. 32) which is probably synonymous with B. chuakensis (Waters, 

 1913, p. 467, see Harmer, 1926, p. 421 footnote). Its spines are more numerous than 

 those of B. chuakensis ; most zooecia having six in the distal series, and one being con- 

 stantly present on the proximal border of the opesia (Fig. 27 A). The symmetrical, 

 median, zooecium, E, at the bifurcation has three spines, one median distal, and one 

 on each side of the proximal end of the opesia, turning outwards. The axillary zooecia 

 F and G are smaller than the rest and have only two spines, one distal and one proximal. 

 The bifurcation is of the type described by Harmer (1926, p. 421) in B. levinseni. The 

 avicularium has a smooth beak, unlike that of B. chuakensis in which it is serrated 

 (Waters, pi. lxviii, fig. 7). 



Cornucopina Levinsen, 1909 

 Key to the species of Cornucopina discussed here 



1. Long, straight, flexibly attached, trumpet-shaped avicularia present. 

 Avicularia all relatively short and either rigidly attached or curved 



2. Outer distal corner extended forming a spine-bearing process 

 No spine-bearing process .. . 



3. Ovicells borne on small adventitious zooecia 

 No special ovicell-bearing zooecia 



4. Ovicells reduced. Stalked basal avicularia 1 gigantic and rare ... 

 Ovicells not reduced. Stalked basal avicularia small and common 



2 

 ... 6 



9. C. moluccensis 



••• 3 



... 4 



■•• 5 



4. C. polymorpha 



3. C. infundibulata 



1 For description of stalked basal avicularium see p. 399. It is to be distinguished from the straight 

 trumpet-shaped type. 



