ECTOPLEUIIA. 123 



from T. coronata chiefly iu its more diffuse habit and the 

 short erect peduncles of its clusters of gonophores ; while 

 from the T. simplex of Alder it is easily distinguished by 

 its branched hydrocaulus [stem] and the greater length 

 of its distal [oral] tentacles." (Allman.} 



Hab. Firth of Forth, from about 15 fathoms ; Shetland 

 seas, from about 50 fathoms (G. J. A.). 



7. T. HUMILIS, Allman. 



" Notes on the Hydroida," Ann. N. H. for July 1864. 



STEMS about 1 inch high, simple or sparingly branched, 

 springing at distinct intervals from the stolon; POLY- 

 PARY light yellow, with nearly obsolete transverse corru- 

 gations; POLYPITES rather small, scarlet, supported on 

 collar-like expansions of the coenosarc; oral tentacles 

 about 15, aboral 20 ; GONOPHORES (male) borne on very 

 short branching peduncles, and forming erect scarlet clus- 

 ters, usually about three in each cluster ; summit of gono- 

 sac with three rather large tentaculiform tubercles. 



" IT resembles T. bellis in its mode of growth and in the 

 shortness of its hydrocaulus [stem] , but is at once distin- 

 guished from this species by the absence of distinct aimu- 

 latiou, and by the smaller size and less appressed form of 

 the polypite." (Allman.} 



Hab. " On rocks close to the level of low-water spring- 

 tides, near the mouth of Kinsale Harbour" (G. J. A.). 



Genus ECTOPLEURA, Agassiz. 



Der. eKTos, without (outside), and TrXevpa, a rib. 

 TUBULARU (in part). 



GENERIC CHARACTER. Stems Jistular, simple or branched, 



