HYDROllJA II 



103 



either side in tlie broad plane of the colony. The h\drotheca has a free adcauline distal wall part, 

 half as long as the hydrotheca or somewhat less, about I'i, times the opening diameter. The hydro- 

 theca has its greatest breadth at the middle, and narrows down both towards the base and towards 

 the opening, which is set perpendicular to the axis of the hydrcHheca. The free portion of the adcau- 

 line wall is as a rule furnished with somewhat faintly marked transverse furrows. The opening margin 

 has four low teeth and four triangular lid plates in the sinuses between them. 



The gonothecte proceed from the branches close under the base of the hydrothecie. They are 

 oval, more or less furrowed transversely in the distal half, and have distally a narrow central opening 

 witl.i two diametrically opposite short broad teeth. 



200 m. 600 m. .._ 1000 m. 2000m. 



Fig. LV, The distribution of Sert!t/aie/la Gayi m the Northern Atlantic. 

 In the hatched region.s a connnon although scattered occurrence is stated in the literature without precise data. 



Material: 



■'Ingolf St. I 62°3o' N., 8°2i' W., depth 132 fathoms 7,2 

 - - 55 63=33' N., 15^02' W., - 316 - 5,9 



85 63°2i' N., 25°2i' W., 



170 



4,1^ 



5>9° 



- 94 64°56' N., 36° 1 9' W., - 204 

 — - 98 65°38' N., 26=27' W., — 138 

 "Thor" 64°o6' N., 23=14' W., — 98 metres | labelled Srrtiilnrrlla polyzo>ii(is\ 



Iceland: Ingolfshofdi 9V2 miles in N. by E.' ,E., depth 53 fathoms. 

 The Faroe Islands: 60=23' N., 8=55' W., - 225 — 



