HYDRO1DA II 



59 



that of Nutting (1900) shows more than most how absolutely indispensable such critical revision 

 really is. It is therefore most correct here for the present to retain a genus such as Polyplumaria. 



Polyplumaria frutescens (Ellis et Solander). 



1786 Sertularia frutescens, Ellis and Solander, The natural history of many curious and uncommon 



Zoophytes, p. 55, pi. 6, fig. a, A, pi. 9, fig. i. 



The colonies are upright and singly or doubly pinnate, with polysiphonic hydrocaulus. The 

 primary stem tube bears on its front a series of hydrothecae, one to three on each internodium ; at the 

 base of each hydrotheca, the tube has an apophyse, which is directed obliquely forward and to the 

 side, alternating to either edge. The apophyse bears a hydrocladium, as a rule secondarily branched, 

 which is at first directed obliquely upward and forward, but gradually turns into the broad plane of 

 the colony. The hydrocladium is divided by transverse nodes into internodia, bearing one to several 

 hydrothecse, and around this a pair of supracalycine sarcothecae, and one median, unpaired, under the 

 base of the hydrotheca. The hydrotheca is fairly large, slender, and fused throughout the whole of 

 one side with the internodium. The secondary hydrocladia proceed from under the base of the basal 

 hydrotheca of the primary hydrocladia, and assume the same appearance as the primary hydrocladia. 



The gonothecae are set on the branches without special protective organs. They are pear- 

 shaped, cut off obliquely distally, with a large lid-bearing opening. 



Material : 



"Ingolf" St 54 63o8' N., isV' W., depth 691 fathoms 3,9 

 - 55 6 3 33' N, I 5 02' W, 316 5,9 



The Faroe Islands: 6i4o' N., f^d W., 135 



16 miles E. by S. of the south point of Nolso, depth 80 fathoms. 



Polyplumaria frutescens has its chief occurrence in the lower parts of the littoral region, and 

 in the upper portion of the abyssal. It is a southern visitor to the boreal seas, having only on a 

 single occasion been encountered in colder water layers, viz. east of Iceland (fig. XXVII). In Green- 

 laud waters, the species has not yet been found, and its occurrence at the Faroe Islands is here recorded 

 for the first time. 



Polyplumaria flabellata G. O. Sars. 



1874 Polyplumaria flabellata, G. O. Sars, Bidrag til Knndskaben om Norges Hydroider, p. 93, pi. 2, 



figs. 16 22. 



Upright, doubly pinnate colonies with polysiphonic branched main stem. The primary tube 

 bears on its internodia alternating apophyses, directed obliquely forward and upward. From the apo- 

 physe proceed the primary hydrocladia, which soon curve into the broad plane. The hydrocladia are 

 divided by almost transverse nodes into internodia, each bearing a large hydrotheca, a pair of supra- 

 calycine sarcothecae, a larger, unpaired proximal, and a smaller unpaired distal sarcotheca in the median 

 line. The hydrothecee are fairly large, about half as long as the internodium; the adcauline wall has 

 a free portion in length about equal to the opening diameter, between one and two thirds of the length 



