34 



HYDROIDA 



a basal whorl of up to 37 tentacles, which, when extended, attain a length of 40 mm. The distal ten- 

 tacles, when extended, attain a length of 9 mm; they are placed in large numbers round the mouth 

 in a main whorl formed by two or more irregular and closely set circles. 



The gonophores are cryptomedusoid and globular ($) or sub-oval (J 1 ), often somewhat tapering 

 distally, but without any rudiments of tentacles. The gonophores are supported by unbranched and 

 strongly contractile blastostyles, which, when extended, attain a length of 40 mm. The gonophores 

 first ripen at the apex of the blastostyle. As many as 32 blastostyles may occur, but, in general, the 

 number is much smaller; the blastostyles arise close above the basal whorl of tentacles. 



Material : 



"Ingolf" St. 102. 6623' N., io26' W., depth 750 fathoms, ~- o9 C. 



- i7- 6533' - io38' - 492 -*- o3 - 



- 139. 6 3 3 6' - 7 3 o' - 702 -S- o6 - 



Greenland: Godthaab (no particulars) [Allman's original specimen of Monocaulus groe nlandica}. 



Davis Strait, depth 100 fathoms [labelled Amalthaca islandica\. 

 Iceland: 66O2' N., no5' W. 



5 miles east of Seydisfjord; depth 435 fathoms. 



The fairly well preserved specimens of the material recently collected show the following cha- 

 racters (all the measurements are given in mm). 



