SEASONAL DISTRIBUTION OF ANCESTRULAE 497 



(1895) an d Scrupocellaria glomcrata Maplestone (1900) both appear to belong to 

 Amastigia as now understood. A. acuminata Maplestone (1900), on the other hand, 

 appears to be wrongly attributed to the genus. 



SEASONAL DISTRIBUTION OF ANCESTRULAE 



Quite a large number of ancestrulae have been mentioned in this report, and the idea 

 at once comes to mind that some evidence of the extent of the breeding period might 

 be obtained from them, for the Cellularine ancestrulae soon break away or become en- 

 veloped in rootlets, and are therefore usually only found on small, young colonies. 



Tables 7 A and B summarize the facts obtained from the collections of Antarctic and 

 sub-Antarctic material examined by me. 



The tables are based on the three big collections which I myself have examined, 

 namely, the collections of the Discovery, the National Antarctic and the Terra Nova 

 expeditions. I do not claim to have found all the ancestrulae, nor even to have searched 

 for them specially, but I have picked over the whole of the material for other purposes, 

 and every ancestrula noticed has been preserved. Thus the tables can be regarded as 

 based on a fairly uniform sampling of the material. They are, however, inconclusive for 

 various reasons. 



In the first place it must be remembered that the ancestrulae are known in only a 

 small proportion of species. Further, it is immediately evident that the abundance of 

 ancestrulae reflects to some extent the intensity of collecting, as indicated by the number 

 of stations per month yielding adult colonies. The average number of ancestrulae per 

 station shows some increase in the warmer months, but this may be due to the chances 

 of a single rich haul. Nearly all the January Antarctic records came from four stations, 

 two of which were made within four days of each other in the Ross Sea ; and more than 

 half the February Antarctic records were from a single station (St. TN 194). 



Nevertheless, there appears to be a distinct tendency in the Antarctic for the ances- 

 trulae only to be found in January, February or March, although adult colonies of the 

 species were collected over a period of 4-7 months. In view of the factors just discussed, 

 I am not sure, however, that this appearance is statistically significant, especially as the 

 few ancestrulae of known date that have been recorded from other collections extend 

 the seasonal range of the ancestrulae as follows: 



Camptoplites 4 (Bugula reticulata var. spinosa Waters, figured), Bellingshausen Sea, 18 October 1898. 



Camptoplites sp. (Bugula reticulata var. spinosa Waters, unfigured), Bellingshausen Sea, 20 December 



1898. 

 Camptoplites areolatus (var. variospinosa Kluge), Gauss-station, 24 April 1902. 

 Camptoplites 3 (Bugula multispinosa Kluge), Gauss-station, 14 June 1902. 



These ancestrulae (which are discussed on pp. 436-441) have been omitted from the 

 table in order that the data given may be based entirely on my sampling and so have, 

 as far as possible, a uniform statistical value. 



The stragglers in the sub-Antarctic table may be misleading. The ancestrulae of 



