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4. Tubulipora cassiformis 1 ) n. sp. (PI. IX, figs 6 — io). 



Type. 94. A. Stat. 119. i°33'.5N., i24°4i'E., 1901 Metres; stony bottom. 



112. A. Stat. 156. o°29'.2S., i30°s'.3E., 469 Metres; coarse sand and broken shells. 



Zoarium reticulate, with the branches arranged in one plane. Strong rooting columns, 

 formed of a bundle of kenozooecia given off occasionally from the basal side of the colony. 

 The branches are commonly parallel to one another, and the cross-connexions are often arranged 

 at the same level in adjacent branches, thus giving rise to elongated, narrow meshes of uniform 

 size. In other parts the meshes may be more irregular. Basal surface smooth, porous, the 

 zooecial outlines indistinct. The branch is subtriquetrous in transverse section, the middle of 

 the frontal surface being the part which is most prominent. This portion is occupied by an 

 alternating series of zooecia, the peristomes of which are somewhat compressed and bend 

 outwards, the orifice being oval and the part of the distal end of the zooecium which faces 

 outwards being flattened. Each "series" of zooecia is thus reduced to a single member, 

 although the outer members are represented by kenozooecia which form the lateral parts of 

 the branch and from which the transverse connexions are developed. Ovicells elongated, usually 

 corresponding in length with about three zooecial series on each side; considerably inflated, 

 the swollen part beginning suddenly at the proximal end. The ovicell encircles the median 

 zooecia on their outer sides, and is here produced into an angular ridge. Ooeciostome short, 

 the ooeciopore being a wide aperture, near the distal end of the ovicell. 



This very characteristic deep-water species is represented in two of the 'Siboga' dredgings, 

 in each case by a small amount of material. The specimens arrived broken, so that it is not 

 possible to decide what was the form of the complete colony. The longest fragment measured 

 about 19 mm. in length. The species is distinguished by its reticulate character, by the reduction 

 of each "series" to a single complete median zooecium and an outer kenozooecium, and by 

 the narrow inflated ovicell. 



The fragments are all flat, the branches being arranged in a single plane. Those from 

 Stat. 119 have elongated meshes, with parallel sides, as shown in fig. 8, a basal view. The 

 connexions between adjacent branches are formed by subcylindrical bundies of kenozooecia, 

 several of which constitute each bundle. In this specimen most of the connexions are developed 

 at the same level in neighbouring branches, so that a very regular disposition of the meshes 

 results. The connexions may be quite transverse, or somewhat oblique; and they are formed 

 from one or both branches. Both these conditions are shown in fig. 8 ; the region where the 

 bundle of kenozooecia meets the other branch or a similar bundle developed from it being 

 distinctly indicated by a suture. Since each bundle dilates as it approaches the suture, a 

 transverse or oblique ridge is formed where two bundies unite. The connecting bundies may 

 have a compressed shape, as shown in fig. 10. A massive column of kenozooecia may be given 

 off by the basal surface of a branch, and 110 doubt indicates an attaching arrangement. 



The specimens from Stat. 156 may have belonged to two colonies, as there are well 



1) From cassis, a net ov cobweb. 



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