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provided with 4 such spines, which form a pretty regular quadrangle, being 

 situated 2 by -2 a little inside each lateral margin. There is a larger number on 

 the 3 lateral rows on either side. The innermost of them has generally one in 

 the outer half besides the 4. The next row has usually one more, but in the 

 outermost row the number is increased to 10 — 12, of which 5 — 6 are situated 

 along the outer margin, 2 — 3 along the outer half of the distal margin, and the 

 rest scattered over the distal half. In the older parts of the colony the projecting 

 covering membrane of the marginal zooecia is connected with the cryptocyst of 

 the lateral walls by 3 — 5 compressed calcareous plates, which spring from each 

 zooecium and are separated by rounded openings. Each of these plates again joins 

 the covering membrane with a thick, quadrangular expansion, which is situated 

 vertically on the compressed part and is slightly bent from side to side in the 

 shape of a roof. This quadrangular expansion has a densely tuberculated outer 

 surface. 



The colony is free, branched, with narrow branches, the zooecia of which 

 are only completely symmetrical in the central portion of the branch and be- 

 come more and more asymmetrical towards the lateral margins. 



Of this form I have examined only a small dry fragment from North Au- 

 stralia, which was kindly placed at my disposal by the late Mr. C. N. Peal. 

 It differs in several respects, for one thing in possessing only a single form of 

 operculum, from the form described by Hincks and Harmer, and perhaps it 

 may be regarded as a distinct species. 



Family Savignyellidae n. f. 



The narrow, elongated, rather slightly calcified zooecia have a frontal surface, 

 provided with scattered pores, which is separated from the basal surface by a 

 more or less sharp boundary line. The distal wall has a number of uniporous 

 or multiporous rosette-plates in its periphery. Spines may appear round the 

 aperture, proximally to which there may be a freely projecting avicularium. We 

 may find free ooecia, two-layered from the proximal part, the ectoooecium of 

 which has a membranous frontal side. The colonies are richly branched, jointed, 

 and each internode consists of a single zooecium. 



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