P<ili/-.(Mt front the Gilbert Islands. 417 



very high, nigose, with small oval avicularia scattered about 

 upon them. Thyrostom.e orbicular, with raised margins ; a 

 wide, deep sinus on the proximal margin. 



This is a very peculiar form. The zooecia are bounded by 

 high, rugose, marginal edges, on which are scattered a great 

 number of small oval avicularia, giving it a very unique appear- 

 ance : similar aviciilaiia are present on tin? siii-face of most of 

 the zodpcia in the distal ])art on each side of the thyrostome. 



Pollaploecium, n. gen. 



Zoarium free, dichotomously brauihed ; branches consisting 

 of internodes, joined by corneous tubes. Internodes composed 

 of six to ten zooecia, united on their dorsal surfaces, facing all 

 ways. Thyrostome with a sinus on proximal lip. 



This genus is near Di plotcluni. Kirkpatrick (recorded from 

 Mauritius), but differs therefrom chiefly by the internodes being 

 composed of six to ten zooecia, whereas in D. simpler (the only 

 species) there are only two in an internode jilaced back to 

 back : the ooecia also are different. 



Pollaploecium gilbertensls, n. sp. (PI. XXVITT., Fig. 18). 



Zooecia oval or pyriform, ventricose : surface minutely punc- 

 tate ; bordered l)y narrow, raised lines. Tliyrostome arched 

 above, straight below, with a dee]) sinus in the middle. Ooecia 

 globose. 



This is the most interesting species in the collection. As 

 noted above, this is near D. ■o'mpler, and I would have placed 

 it in the same genus, but the number of zooecia in an internode 

 is made a generic distinction by Kirk])atrick. The ooecia are 

 placed above the zooecia. and are continuous with them, only 

 a slight suture showing the line of demarcation between them. 



Mucponeila umbonata, n. sp. (PI. .X.Will.. Fig. 19). 



Zoarium encrusting. Zooecia iinnicrsed, area undeiined : 

 surface with stellate and irregularly-shaped pores. Tliyrostome 

 orbicular. Peristome much elevated, with a straight, narrow, 

 deep notch in the side ; one side of which is more or less raised 



