64 S. v. Clark on New and Rare, Species of Ilydroids. 



H. articulosiini resembles H. pluniosiini^ but has a stouter habit ; 

 the iuteruocles are shorter and stouter ; and it may also be dis- 

 tinguished by the direction of the joints, at right angles to the stem, 

 and by the very wide-mouthed calycles. The female gonothecse some- 

 what resemble those of M. Beanii^ but are of a stouter build ; they 

 are relatively larger at the distal extremity, the orifice is differently 

 shaped and is differently situated, being nearer the distal extremity. 



Sertularia argentea Ellis and Soiander, vaj\ divaricata nov. 



Plate X, fig. 7. 



Stem simple, stout, erect, straight or slightly flexuous, of a deep 

 horn color, regularly jointed, each joint having two or three branches ; 

 branches alternate, sparingly branched, diverging at right angles 

 from the main stem and all in the same plane, divided quite regularly 

 by joints, each bearuig two pairs of hydrothecte, much resembling 

 a young shoot of the usual form of S. argentea. Hydrothecte nearly 

 opposite, curving strongly outwards, with a bilabiate mouth, the 

 upper lip being considerably smaller than the lower ; hydrothecse are 

 also scattered along the stem in pairs. Gonothecae unknown. 



Collected at Oasco Bay, Me., 1878, — U. S. Fish Commission. 



I at first thought that this was a distinct species, but I have since 

 had intermediate forms which prove quite conclusively that it is only 

 a variety of S. argentea. Considerable variation is shown in the 

 hydrotliecae of this variety ; some of them, on the same stem, are 

 more directly opposite and curve outwards more than others. 



Plumularia Verrillii, sp. nov. 



Plate X, fig. 9. 



Stems erect, simple, straight or slightly curved, slender, two to 

 four inclies high, of a bright horn-color, branched and regularly 

 jointed by transverse divisions; the branches have their origin near 

 the base of the stem, are ei-ect and resemble the main stem in all par- 

 ticulars; pinnae occasionally branched, regularly arranged on two 

 sides of the main stem and branches, sej^arated by an angle of ninety 

 degrees, composed of long similar joints, each bearing a hydrotheca 

 and a number of nematophores ; occasionally there is an odd, intermedi- 

 ate joint bearing only one or two nematophores and no hydrotliecae ; 

 a single pinna to each joint. Nematophores sessile, compound, large, 

 tapering to the base, with a round cup-like opening : there are four 

 to six on each hydrotheca-bearing joint, one on eacli side of the upper 



