or Little-hnoiun, Polyzoa. 181 



curious, and is precisely similar to what occurs in Lehy- 

 thopora hystrix. On the specimen there is a single spatu- 

 ]ate vicarious avicularium, similar also to those of Leky- 

 thopora. There are no ooecia on the specimen. 



Family iDMONEiDiE. 



Id'inonea atlantica, E. Forbes. 



Two forms of this species occur, for specimens of both of 

 which I am indebted to Mr. Wilson. Of one I have only 

 seen a single specimen, three-quarters of an inch in height. 

 The branches are dichotomous, and spread in nearly the same 

 plane. Thezooecia are three to five in a row, the peristoroes 

 very long, the innermost the longest. The posterior surface 

 is regularly longitudinally grooved in the growing ends of 

 the branches, the ridges punctate; but in the older parts 

 the ridges and intervening grooves are much obscured by a 

 series of close concentric ridges, similar to those in /. 

 Milneana and interjunda. In the other form (var. tenuis, 

 Busk) the branches are narrower, much more straggling, 

 and the posterior surface has not the concentric ridges. 



Hornera ramosa, n. sp. Plate I., fig. 4. 



Zoarium branched, spreading ; branches irregularly in the 

 same plane. Branches rather narrow; anterior surface 

 fibro-reticulate, the zocecia opening in rhomboidal spaces. 

 Zooecia in three to five rows, orifices exserted, the central 

 circular and entire, the lateral elliptical and pointed at one 

 side. Posterior surface grooved, the ridges punctate and 

 frequently separated by large punctations or vacuoles. Ocecia 

 posterior, prominent, surface deeply areolated, frequently 

 crossed by a narrow ridge starting from the aperture, which 

 is nearly lunate and at one edge. 



Port Phillip Heads and elsewhere. 



I have some doubt whether this should not be considered 

 a slender variety of H. frondiculata, which again ought 

 possibly to be referred to H. lichenoides. It occurs in small 

 tufts, occasionally attaining a diameter of an inch. The 

 zoarium arises from a spreading, fibrillated, encrusting base, 

 the resulting short stem immediately dividing into two or 

 more. These again divide dichotomously, or give ofi" smaller 

 branches from the sides. The branches sometimes arise 

 irregularly, and are slightly twisted on themselves, but they 

 usually spread in a more or less flabelliform manner, 



