HIMANTOZOUM 423 



The affinities of Calvet's species appear to be with the Bicellariellidae rather than the 

 Flustridae. Of the described genera of the family it approaches most closely to 

 Himantozoum Harmer (1923, p. 311 ; 1926, p. 453) with which it agrees in the form of 

 the colony and zooecia, in the method of bifurcation and in the possession of a distinct 

 operculum. It differs in the absence of avicularia and the presence of ovicells, but the 

 ovicells are shallow and, as noticed by Calvet, only accommodate a small part of the 

 embryo. The difference between H. taurinum with its internal ovisacs and H. ant- 

 arcticum with shallow ovicells appears unimportant when one considers the great 

 similarity of their zooecial and zoarial characters, especially as H. sinuosum and 

 H. obtusum sp.n. have rudimentary ovicells of intermediate character. 



In comprising species both with and without avicularia, and showing a graded series 

 of ovicells Himantozoum would resemble other genera of the Bicellariellidae, particularly 

 Beania. There is thus justification for modifying the definition of Himantozoum, in 

 these ways. A list of the species that I include in Himantozoum is given in the legend 

 to Fig. 63, p. 494. 



Bugula versicolor Busk (1884, p. 38) is still excluded from Himantozoum by its large 

 endozooecial ovicells, which are very different from the shallow hyperstomial ovicells 

 of H. antarcticum and, as suggested by Harmer (1926, p. 454), may relate it to the Farci- 

 minariidae. Although they are immersed in autozooecia instead of kenozooecia, they 

 have much in common with the ovicells of Kenella biseriata which should, in my 

 opinion, be placed in the Farciminariidae (see p. 394). 



There is some variation in the position of the spines on the fertile zooecia in Himan- 

 tozoum antarcticum. They may be directed distally or obliquely inwards, but in this 

 material they seldom have the almost transverse position shown in Calvet's figure. The 

 fine colony from Bransfield Strait has branches with as many as eleven series of zooecia. 



A young colony from St. 1660 (Ross Sea, 27 January 1936) consists of an ancestrula 

 and seven zooecia arranged in a single series. The ancestrula is attached by its slightly 

 expanded base, and both the ancestrula and the succeeding zooecia are typical in shape 

 with the opesia occupying the greater part of the frontal surface and the distal corners 

 pointed. Each zooecium gives rise to a rootlet proximally from the lateral wall, and 

 these rootlets adhere to the basal surface of the colony. In six other young colonies 

 from St. 1660, the number of zooecia in the basal uniserial portion of the colony varies 

 from four to nine. The figured ancestrula (Fig. 37 B), which is exactly similar in shape 

 to those from St. 1660, came from St. TN 194 (off Oates Land, 22 February 191 1). 



The "stalk", mentioned by Harmer (1923, p. 311), is formed by rootlets enveloping 

 the zooecia of the more proximal parts of the colony, as described by Calvet. In some 

 specimens these rootlets are calcified. 



Since this report was in proof I have seen a paper by Braem (1940, p. 675) who finds 

 that the alimentary canal of Bugula apsteini, which I have included in Himantozoum, 

 shows the same peculiarities as the other forms of Himantozoum examined by him, namely 1 



1 Braem examined material from the Deutschen Tiefsee Expedition. He does not mention varieties or 

 forms, but according to Hasenbank ( 1 93 2) the expedition did not obtain the typical forms of these two species. 

 The question whether Hasenbank's material of H. sinuosum is distinct from the typical form is discussed below. 



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