460 DISCOVERY REPORTS 



out its length (Plate IX, fig. 4), and as marked differences in calcification were observed, 

 they may be supposed to give a fair idea of the phases of calcification. 



Fragments of a species of Camptoplites, judged from the shape of its zooecia and small 

 avicularia to be one of the forms of C. latus, were taken by the ' Quest ' at South Georgia 

 (23 . 12. 1 .34, 36). Unfortunately, there are no large avicularia and no ovicells, but the 

 small spines are directed frontally in some zooecia, distally in others, as in var. aspera, 

 the only form of the species known from South Georgia. The fragments show an axillary 

 rootlet with an elaborately branched terminal disk, and also the formation of a branch 

 by regeneration from the distal part of a single damaged zooecium. 



16. Camptoplites atlanticus sp.n. Figs. 40, 51 A-C. 



Station distribution. Sub- Antarctic: South Atlantic Ocean, Sts. WS 93, WS231, WS 773, 

 WS 824. 



Geographical distribution. Patagonian Shelf, and off the shelf down to 293 m. (Discovery). 

 Holotype. St. WS 773. 



Description. Colony with two to seven (or more ?) series of zooecia, no secondary 

 branches. 



Rootlets arising from lateral and axillary chambers, both with runners (Fig. 51 A). 

 Axillary chambers without rootlets also present. Cross-connexions common. 



Zooecia with their distal ends raised and, in the marginal zooecia, turning away from 

 the median line of the branch. 



Spines absent. 



Avicularia (Fig. 5 1 B) all of one kind, longer than high, the lower head-angle about 90 . 



Ovicells (Fig. 51 C) about as wide as high with pronounced radial striation or fluting 

 which shows no tendency to be superseded by other sculpture. 



Ancestrula (Fig. 40) vase-shaped, with long opesia and short stalk, attached by roots, 

 spineless (species 2, p. 439). 



Remarks. This species is related to Camptoplites latus. It differs in the complete 

 absence of spines throughout the colony, in the avicularia which are all of one kind and 

 differ in shape from those found in C. latus, and in the ovicells in which the original 

 radial striation is pronounced and, as far as the evidence goes, permanent. The avicularia 

 are longer in proportion to their height than the small avicularia of C. latus, and the 

 lower head-angle, which is acute in C. latus, measures about 90 (cf. Figs. 48 F and 51 B). 



Three young colonies are attached to the type specimen. Each consists of an 

 ancestrula and a few zooecia. The complete absence of spines even on these young 

 colonies is remarkable. Avicularia, of typical shape, are present on the second and 

 subsequent zooecia. The stalk of the ancestrula is very short as compared with other 

 known ancestrulae of Camptoplites, and ends in two to four roots which may be sym- 

 metrically arranged, as in the figured specimen, or may be more irregular. Their tips, 

 like those of the ordinary runners and rootlets of the adult colony, tend to be in contact 

 with rosette-plates, but here they are the rosette-plates of the supporting colony. The 

 connexion of a rootlet of one colony with the rosette-plate of another colony seems 



