V. *07. 20 



are free for nearly the whole of their length, and are only 

 united very close to the base. The siphonozooids are numerous 

 on all parts of the rachis except along the median line of the 

 dorsal surface, and at the top of the rachis, which ends in a 

 naked cone-shaped extremity. Small groups of siphonozooids 

 occur between the autozooids, and sometimes encroach on 

 their bases. 



The specimen is viviparous. 



The calcareous axis is four-sided, with rounded edges. 

 Three of the sides are deeply grooved, while the remaining 

 one, which is ventral in position, has an almost flat surface. 

 At a point slightly below the swelling in the penduncle the 

 three grooved sides each measure 3 mm. across, while the 

 fourth has a breadth of 5 mm. 



In the description of the type no mention is made of the 

 occurrence of spicules in the peduncle, but numerous cal- 

 careous spicules, similar to those in Anthoptilum, are found at 

 the base of the peduncle in the Irish specimen. They are 

 oblong in shape, and are often united in groups of four. They 

 vary in size from '007 mm. -'022 mm. by '005 mm. -'007 mm. 



In the arrangement of the autozooids and* siphonozooids 

 there is an exact agreement between the Irish and the Ameri- 

 can specimens. The only difference lies in the measurements 

 of the different parts-. The former specimen is of a stouter 

 growth, with shorter autozooids, while the latter has a more 

 slender stem and rachis and much longer autozooids, as will 

 be seen from the following measurements : 



Irish specimen. Type specimen. 



Total length, 365 mm. 300 mm. 



Length of stalk, . . . .90 mm. 93 mm. 



Diameter of stalk, . . . .11 mm. 5 mm. 



Diameter of rachis, ... 12 mm. 6 mm. 



Length of autozooids, . . . 30 mm. 58 mm. 



(including tentacles). 



In spite of these differences in size it does not seem that there 

 are sufficient grounds for creating a new species for the Irish 

 specimen. 



There has been no record of Benthoptilum sertum since the 

 three type specimens were dredged by the Albatross in the 

 North Atlantic, off the eastern coast of the United States, at 

 depths of 843 to 1,073 fms., but a Pennatulid was taken by 

 the Travailleur off the coasts of Spain and Portugal (Marion, 

 1906) which bears a resemblance to it. The Travailleur 

 specimen is unnamed and undescribed, but as far as can be 

 judged from the figure given it resembles the Irish specimen 

 fairly closely, and may be a young specimen of the same 

 species. 



I have to thank Professor J. Arthur Thomson for very 

 kindly examining this specimen and giving me his valuable 

 opinion regarding it. To him is due the interesting discovery 

 of tho viviparity of the species, concerning which he notices 

 that the free embryos in the coelenteron are remarkably large 

 and clear. 



