134 BULLETIN OF THE 



HIPPURELLA, Allman. 



The genus Hippurella. was founded by AUman for those hydroids in which 

 the proximal ends of the branches are piuately branched, while the distal end 

 of the same bears verticillately arranged branches. Allman speaks of the last 

 as if they were the same as the piima:. They ai-e, however, destitute of hydro- 

 thec£E, and simply bear a row of nematophores. Their function is the protec- 

 tion of the gonophores, which are confined to this region of the hydrosome. 



Hippurella annulata, All. 



Tropbosome : — Hydxocaulus six to eight inches tall, for two thirds its 

 length without branches. Branches alternate, bearing ultimate ramuli. Base 

 of hydrocaulus developed into disk-shaped hydrorhiza. Stem fascicled. Pinnae 

 opposite, although those of opposite sides do not lie in the same plane. Inser- 

 tions of pinna; alternate. Hydrothecaj separated from each other on the stem. 

 In the interval between two hydrothecse, there are four or five partially formed 

 annulations- Mesial nematophores free, long, and two in number. Margin of 

 the hydjotheca smooth and circular. Supracalycine nematophore overtoj^ping 

 the orifice. A single ultimate branch, or pinna, arises from the main stem. 



Gonosome : — The distal extremity of the branch is modified into a gono- 

 some. The proximal end of each branch bears pinnaj regularly arranged as 

 described. Those on each side lie in one and the same plane. They pass with- 

 out great modification into the verticilhitely arranged ribs of a gonosome at the 

 distal end of the branch. The ribs which compose this gonosome are undi- 

 vided, and without branches. Each A^erticil is composed of six ribs of equal 

 size and shape. At the base of the verticil, in the angle which the ribs make 

 with each other, there is a single nematophore. The ribs arise at right angles 

 to the stem, and at a short distance from their origin curve upward. Near this 

 bend they bear a pair of nematophores, one on each side, while higher up in 

 their course the ribs bear single rows of nematophores. Gonophores seated in 

 the interval between successive verticils of these ribs. 



St. Vincent, 124 fms. 



CALLICARPA, n. g. 



Callicarpa differs from all the other genera of hydroids yet described in the 

 character of the gonosome. The gonosome resembles closely a spike of wheat, 

 and springs by a short peduncle immediately from the main stem. It is mor- 

 pliologically speaking as if the proximal part of the branch which bears pinnae 

 in Hi'irpurdla was reduced to a peduncle, and the distal end with its verticillate 

 ribs became the gonosome. 



Callicarpa gracilis, n. s. 

 Trophosome : — Hydrocaulus rising to the height of six inches from a tan- 

 gled mass of filaments which form the base of attachment. From a point about 



