OF THE NORTH-POLAR EXPEDITION. 237 



1. The far smaller size of the zoarium, which probably does not 

 exceed an inch in height, and the cylindrical form, for the most 

 part, of the stem and branches. 



2. The smaller dimensions of the avicularium, and more espe- 

 cially of its mandible. 



3. The tripartite dentition of the anterior or inferior lip. 



4. The deep immersion of the mouth and of the orifice of the 

 avicularium in the older stages of growth, these parts, in fact, in 

 the stem and lower part of the branches being entirely overgrown 

 and obliterated. But before the complete closure is effected, the 

 mouth of the zooecium, with the orifice of the avicularium arid the 

 median denticle immediately behind it, may be seen at the bottom 

 of a deep pit, the mouth at this stage presenting a trefoil form, 

 like the wound made by a leech-bite. 



3. Eschara Sarsii, Smitt (sp.). 



Escharoides Sarsii, Smitt, I. c. 1867, pp. 24 & 158, pi. xxvi. figs. 147- 



154. 

 Eschara rosacea, Sars, N. Norsk. Polyz. p. 3 (non Busk). 

 Cellepora cervicornis (var.), Sars, Reise Lof. og Finm. p. 28. 



Bab. Franklin-Pierce Bay, Smith's Sound, 13 f ins. (H. W. F) ; 

 Spitzbergen, 20-60 fms. (Smitt) ; Greenland (Holler Sf Torell) ; 

 Einmark, 80-100 fms. (Sars, Sfc.) ; Arctic Sea (Sir Ed. Belcher's 

 Expedition)-, in lat. 74° 0' S., 172° 0' E., 330 fms. {Rookery 

 Voyage of ' Erebus ' and ' Terror '). 



In all the specimens I have examined in the present collec- 

 tion there is only a single avicularium on one side of the preoral 

 sinus. The species is particularly interesting as being identical 

 with one, of which I have specimens, collected by Sir J. Hooker, 

 on the voyage of the ' Erebus ' and * Terror,' in the Antarctic 

 seas, accompanied in the same collection by two other Arctic 

 species. 



Genus Hemeschara, Busk. 



1. Hemeschara sincera, Smitt (sp.) (var. inermis). 

 Discopora sincera (forma Hemeschara), Smitt, I. c. 1867, pp. 28 & 177 



pi. xxvii. figs. 1 /B— 1^0. 

 Lepralia (Discopora) sincera, Hincks, I. c. p. 102. 



Bab. Eranklin-Pierce Bay, Smith's Sound, 13 fms. (on Celle- 

 pora cervicornis) (H. TV. F.) ; Spitzbergen, 19-60 fms. (Smitt) ; 

 Einmark (Loven) ; Arctic sea, ?, 100 fms. ( Wallich !) ; Hare 



