Hydroida from Iceland. 151 



cientl J marked, and I have no doubt that the species is distinct 

 from anj hitherto described. It makes the nearest approach 

 to H. labrosum^ Alder ; but its calycles are very diflPerent from 

 those of the latter species. They are not annulated towards 

 the base, nor have they the much everted rim so characteristic 

 of H. lahrosum. The lower portion, supporting the cup in 

 which the base of the polypite is lodged*, is perfectly plain, 

 or exhibits only a slight twist near the point of origin. The 

 whole hydrotheca is trumpet-shaped, expanding gradually 

 upwards towards the margin, which is but slightly everted. 

 From the lower part, a little beneath the cup, a short, strongly 

 annulated branchlet is given off. Frequently the primary 

 calycle supports a second, as is commonly the case in this 

 genus, which rises from within it. 



The stem is very regularly and distinctly crenulated above 

 each joint; and this^s a marked character, giving a very ele- 

 gant appearance to the species. On the portions which I have 

 had the opportunity of examining there were sometimes short 

 branchlets alternating with the calycles, and exhibiting the 

 same structure as the larger stems. The lateral processes 

 supporting the calycles are very short. The gonothecae are 

 ovate, membranous, borne on a short stalk which is not 

 ringed, and are developed on the lateral process. The stems 

 are of a dark horn-colom\ 



Family Sertulariidse. 

 SertuJaria tenera^ G. O. Sars. 



One or two specimens occur of this interesting form, which 

 has recently been obtained at gi-eat depths (150 fathoms) off 

 the coast of Norway by G. O. Sars. 



Serhdarella tricuspidata^ Alder. 



Very abundant and fine. 



Sertularella polyzonias, Linn. PI. VII. figs, 11, 12. 



Abundant. 



The robust habit and gigantic calycles give a very marked 

 character to the northern variety of this common species. So 

 distinctive is its a])pearance that, while there are no differences 

 entitling it to s])ecific rank, it is worthy of being recorded as 

 S. polyzoniasy var. gigantea. Sars mentions a robust variety 



* The polypites of Hahchim are only partially retractile ; and little 

 more than the base of the body is contained in the cup-like chamber 

 which forms the upper portion of the hydrotheca. The lower portion is 

 tubular, and in the present case almost plain throughout, whereas in 

 H. lahroHum it is strongly annulated near tlie base. 



