235 



hers liave a rather large, oblong, frontal opening. On the adzooecial side of the 

 daughter-zoa-ciiim the three distal chanihers have coalesced into a single cavity, 

 and an aviculariuni is accordingly wanting. The niolher-zoa'ciuni has a very 

 small, slit-like, infra-scapular adzorecial chamber. 



The ooecium (PI. XII, (ig. 1 k). The gonozooecium, which sometimes springs 

 from a mother-zo<L'cium, sometimes from an inserted single zoa-cium, is approxi- 

 mately of the same size as the covering kenozooecium, and together they are of a 

 broad, hexagonal ly rounded form with two parallel lateral margins curving in- 

 wards a little. The sternal area has .'5 small fenestra- and 3 — 5 spines separated 

 by short fissures. The two distal spines, which meet in the oral suture, have a 

 large inner cavity connected with a large oval pore in the oral margin. The 

 others are very short and generally have no inner cavity. Within the very broad 

 fenestra; of the kenozocecium pores as well as numerous spinous processes are 

 seen, while the supporting |)rocesses, which reach the calcareous roof of the keno- 

 zoa^cium, are most numerous in the portion between the two fenestra.*. On the 

 side of these fenestras we find a continuation of this median portion, which goes 

 as far as the aperture and is bounded by two lateral margins converging towards 

 the latter. A small median chamber may appear on the top of the kenozooecium. 

 It is always found in specimens from the Bass' Strait, in which it is very oblong 

 and provided with one or several slit-like openings in the roof. On the other 

 hand its appearance is very inconstant in colonies from Port Phillip, in which 

 il is very small, oval and only calcified at its base. 



Form of colony. In all the principal branches and sometimes also in some 

 of the secondary branches two bizoa'cial internodes succeed each other (2, 2, 1, 

 2 2 1 ) 



Of this species I have examined colonies from Port Phillip and the Bass' 

 Strait. 



Costicella cuspidata n. sp. 



! 1>1. XX, ligs. f) a-(i c). 

 The sternal area, which may be longer Iban the aperture by a half, is j)rovided 

 with 7 — 10 small feneslraj disposed in a broad curve, and within these there are. 

 6 — 8 smaller ones, of which one is generally situated in the central line far back. 

 In the central portion of the area we see three, more seldom four s]iines, of 

 which the Iwo large, plate-shaped distal ones have an inner, most IVeipieiiliy 

 three- or four-branched cavity connected with as many pores, of which we usu- 

 ally find one on each side of the proximal margin of the aperture. Very often, 

 perhaps in most cases, the cavities of the two large spines communicate through 



