300 SIDNKY V. JiAiari']!;. 



Proximal piiii of the frontal sliiekl with munerous large 

 pores, which do not extend to the distal end of the zooecium. 

 The oral end of the zooecium may be somewhat raised above 

 the general surface of the flat frontal sliield. A rounded 

 suboral lobe occurs, and may have almost the appearance of 

 a nmcro. Ordinary orifices and opercula somewhat longer 

 than broad, witli a concave proximal margin, 210 — 250 /x 

 broad; fertile zooccia with trifoliate orifice and operculum, 

 320 — 34-0 ft broad. External ovicells only represented by the 

 somewhat hood-like calcareous wall at the distal end of the 

 zooecium. An avicularium, with long linear mandible, 

 commonly occurs on one side of the orifice. Basal surface 

 smooth, its intersection with the four vertical walls forming a 

 regular oblong. Pore-chambers absent. 



Torres Straits, A. C. Haddon collection, 1888-0. 



This species somewhat resembles L. f eegeensis. Busk, but 

 differs from it in the absence of external ovicells. It is of 

 interest in throwing light ou the meaning of the occurrence 

 of dimorphic o])ercula. The outline of the ordinary opei"- 

 culum (fig. 38) is not unlike that of the A-opercula in 

 Euthyris obtecta. The B-opercula are much w'ider, and 

 are trifoliate. In either kind of zooecium there may be au 

 avicularium on one side of the orifice, its acute mandible 

 sloping, when closed, towards the distal end of the zooecium. 

 The compensation-sac is present in both kinds of zooecia, 

 and has typical parietal muscles. In some zooecia it contains 

 long wavy filaments, which may be parasitic Alga3 or Fungi. 

 In the zooccia with trifolate operculum an ovary (fig. 39) is 

 developed at the basal end of one of the lateral walls. A 

 spherical ovisac, with delicate walls, makes its appearance at 

 the distal end of the zooecium, ou the basal side of the oj)er- 

 culum and tentacle sheath. Into this sac are inserted 

 muscle-fibres, which radiate to it from the adjacent parts of 

 the basal and lateral walls. In one zooecium an vij;y^ has 

 maturcnl and has become filled wilh yolk, its diameter nearly 

 eipialling that of the zoeeciuni. This eg^ has passed into the 



