152 HYALONEMA. 



Of the species hitherto described there is, besides the one reexamined by 

 me which is referred to above, one {H. pellucidum Ijmia) at least, probably 

 several, which can be referred to this subgenus. 



In two of the Pacific species examined one kind of amphidisc has broad and 

 rather low, umbrella-like amphidisc-anchors. For these I establish the sub- 

 genus Skianema. 



In one of the Pacific species examined I found a peculiar kind of amphidisc 

 with from one to three branches on the convex side of some or most of its anchor- 

 teeth, which give to the anchors the appearance of being doubled. For this 

 species I establish the subgenus Thallonema. 



The remaining species of Hyalonema, in which none of the different kinds of 

 peculiar amphidiscs referred to above occurs, can be divided, in accordance with 

 the primary division used in F. E. Schulze's key, into those in which the largest 

 amphidiscs are stout and have a thick shaft; subgenus Hyalonema, and into 

 those in which these amphidiscs are slender and have a thin shaft; subgenus 

 Leptonema. 



Nine of the Pacific species examined by me, two of which were insufficient 

 for exact description and for naming, and the great majority of the species of 

 Hyalonema previously described, belong to the subgenus Hyalonema. 



One of the Pacific species examined by me, and at least five previously 

 described species {H. poculum F. E. Schulze, H. solutum F. E. Schulze, H. 

 urna F. E. Schulze, H. divergens F. E. Schulze, H. depressum F. E. Schulze) 

 belong to the subgenus Leptonema. 



Possibly H. lusitanicum Bocage and H. cupressiferwn F. E. Schulze men- 

 tioned above as probably belonging to the subgenus Prionema, and H. ovuliferum 

 F. E. Schulze assigned to the subgenus Oonema may also belong to the subgenus 

 Leptonema. 



HYALONEMA (Gray) Lendenfeld. 



Species, the amphidiscs of which have hyperbolical, semispherical, or bell- 

 shaped terminal anchors from about one fourth to one third of the whole spicule 

 in length; without amphidiscs of any other kind. The largest amphidiscs are 

 stout and have a thick shaft. 



The collection contains twenty-three more or less complete specimens and 

 three fragments of this subgenus. Two of the specimens, apparently represent- 

 ing two distinct forms, could not be specifically determined; the twenty-one 

 others and the three fragments belong to seven different species, all of which 

 are new. 



