i50 



The present species is represented by a single fragment; obtained, with H. spinigera, 

 from Station 105. It may be described as a very typical form of its genus, but the material 

 is hardly sufficiënt to enable it to be determined with certainty. It is probable, however, that 

 it belongs to IL caespitosa, described by Busk from Cape Capricorn, Oueensland. The ovicells 

 of a form from near Marseilles referred to H. caespitosa have been described by Calvet *) ; 

 although it seems not improbable that the specimens figured really belonged to H. frondiculata. 

 Measurements, in u. : 



Diameter of branch, at lovver part of fig. 13, 1,020; 



Diameter of branch, at left side of the same, 600 ; 



Diameter of orifices, 75 — 100. 



Fam. Cytisidae D'Orbigny. 



Cytisidae D'Orbigny, 1S54, "Pal. Franc. Terr. Crét.", V, p. 1042. 



Cytisidae Pergens, 1890, "Rev. Bry. Crét. figurés par d'Orbignv", Buil. Soc. Beige Géol., 

 III, p. 384- 



The Family Cytisidae, as defined by Pergens, consists of species in which the colony 

 consists of free branches or is discoidal, having the orifices placed in groups on one of its 

 surfaces. The peristomes are not prominent, and accessory pores are present. The ovicells are 

 rounded swellings placed on the oral surface. 



The only species corresponding with this definition which was found among the 'Siboga' 

 dredgings may be referred to Supercytis D'Orb. : — a type which, according to Pergens, is 

 assumed by young colonies of forms referable to other genera, in which the branches are not 

 yet much developed. The occurrence of ovicells in the specimens described below seems to 

 show, however, that the adult features of the species are more or less developed in a form 

 which has the Supercy tis-cha.ïa.cters. A number of fossil species of this type are known to 

 Palaeontologists ; and much difference of opinion exists as to their classification. The material 

 at my disposal is not sufficiënt to enable me to attempt to reconcile these differences; but for 

 a critical discussion of the subject I may refer to Gregory's work : ) published in 1909. 



Supercytis D'Orb. 



Supercytis D'Orbigny, 1S54, t. cit., p. 1060. 



Supercytis ? Waters, 1884, Toss. Cycl. Bry. Australia", Q. J. Geol. Soc. XL, p. 692. 



Supercytis (pars) Busk, 1S86, Challenger Rep., L, p. 28. 



Supercytis Waters, 1914, "Mar. Faun. Brit. E. Afr.", "Bry. Cycl.", Proc. Zool. Soc, p. 837. 



Fascicidipora (pars) Busk, 1875, "Cat. Mar. Pol. Brit. Mus.", III, p. sy. 



As defined by D'Orbigny, this genus consists of pedunculate forms, spreading out above 

 and giving rise to simple or bifurcate branches diverging horizontally but united at their bases. 



1) Calvet, L., 1907, "Bryozoaires", Exp. Sci. Travailleur et Talisman, VIII, p. 47S, PI. XXX, tigs 11, 12. 



2) Gregory, J. W., 1909, "Cat. Foss. Bry. Jirit. Mus.". "Cret. Bry.", II, pp. xxiv — xli. 



150 



