HYDROIDS OF BEAUFORT, NORTH CAROLINA. 



371 



lished, since the gonophores do not produce free medusae. To that genus I have given the name 

 Scandia. The specific name "mutabilis" has priority and has therefore been retained. 



Prof. Nutting has kindly given me permission to use the family name, Hebellidse, in this paper. 

 It thus appears containing the two genera Hebella and Scandia. 



Key to the Genera of the Hebellid.e Found in the Beaufort Region. 



A. Gonophores producing free medusae Hebella. 



B. Gonophores producing sporosacs Scandia. 



Genus HEBELLA. 



Trophosome. — Colonies consisting of single hydrantlis attached by short pedicels to a stolon, which 

 usually creeps over other hydroids. A distinct diaphragm is present in the hydrotheca. 



Gonosome. — Gonophores producing free medusae. 

 Hebella calcarata (A. Agassiz). 



Laf(xa calcarala A. Agassiz. North American Acalephae, 1865. p. 122. Hargitt, American Naturalist, 1901, p. 387. 

 Hebella calcarala Nutting, Hydroids of the Woods Hole Region, 1901, p. isi- 



Trophosome. — Colony commonly creeping on other hydroids, especially sertularians, in which case 

 the stolon may creep along the axis of the sertularian and give off its hydrothecae more or less regularly 



Fig. 35. — Scandia mutabilis (Ritchie). .\. B and C. different forms of hydrothecae; D, female eonosome; E. male gonosome. 



and symmetrically, so that at first glance it looks like part of the sertularian colony. Occasionally a 

 small portion may become erect without supjwrt. When the stolon creeps over an erect hydroid, the 

 hydrothecae may be given off in pairs, but this is not always the case. When a stolon creeps over a 

 horizontal surface, the hydrothecae are given off singly. They are tubular, about three times as long 

 as broad, with a smooth surface, attached by means of a very short pedicel; they may be bent so that 

 the sides may form a very distinct curve. 



Gonosome. — Gonangia quite large, from one and a half to two times the length of the hydrothecae, 

 attached to tlie stolon by short pedicels; they are broad at the distal end and taper gradually to the 

 proximal; the opening does not occupy the whole of the distal end. 



Distribution. — Found most commonly growing over Pasylhca quadridentata, but occasionally on 

 other hydroids and quite often directly on the surface of the gulfweed to which these hydroid hosts 

 were attached. 



Genus SCANDIA, new genus. 



Trophosome. — Colony simple, creeping, giving off single individuals at intervals along the stolon; 

 hydrothecas tubular, with narrow diaphragm and entire margin; proboscis dome-shaped. 

 Gonosome. — Gonophores producing sporosacs. 



