Haddon AND SHACKLETON~J.ci;/mcB.- I. ZomitJiece. 697 



mesenteries in other resjDects seem to be very similar to those of P. howesii and P. 

 kochii. Well marked sinuses extend through each mesentery from the base to 

 the disc. 



Gonads. — We have found no generative organs in this species. 



The more irregular disposition of the polyps distinguishes P. kochii from P. 

 howesii, in which they are arranged more or less in rows. The zigzag appearance 

 due to the partial immersion of the polyps is very characteristic of P. hoivesii. It 

 would require considerable care to distinguish between P. kochii and certain other 

 species of the genus. P. coesia, as identified by ourselves, is easily distinguishable 

 from the preceding species on account of the large and non-crowded polyps and 

 the apparently smaller size of the colonies ; but we would like to add another 

 warning as to the extreme difficulty in identifying the species of this genus. 



SPHENOPXJS, Steenstrup, 1856. 



Free, solitary, brachycnemic Zoanthese, with a single, very long, mesogloeal 

 sphincter muscle. The body-wall is incrusted. Cell islets present in the mesogloea. 



Sphenopus arenaceus, Hertwig. 



Sphenopus arenaceus : 



Hertwig, 1882, Voy. H. M. S. " Challenger," Zoology. Report on the Actiniaria, p. 120, pi. u., 

 fig. 10 ; pi. xrv., fig. 8. Also, 1886, ibid., Supplement, p. 52. 



Hertwig says, in his first report of this species : — " Habitat — Cape York ? (the 

 title of the label enclosed with the preparation was nearly entirely destroyed 

 by the rough surface of the animal, and could not be exactly made out), one 

 specimen." In the Supplement he says : — "Habitat — Station 187, Torres Strait, 

 Australia, Sei^tember 9, 1874 ; 6 fathoms. Two specimens. ... In the ' Chal- 

 lenger' material I have found four further examples of the genus SphenojDus ; two 

 of these I have determined as Sphenoptcs arenaceus, on account of their rusty red 

 tint, and other two 8phenopus marsupialis, in consequence of the earthy-gray colour 

 and the absence of a stalk." The last being a character of his other new species, 

 S. pedunculatus {I. c. p. 49), from off Panay, Philippine Islands. 



This is the only Zoajithean previously recorded from Torres Straits, and it does 

 not occur in our collection. Thanks to the kindness of Professor F. Jeffrey Bell, 

 of the British Museum, we have been able to examine some specimens of >S'. mar- 

 siipialis which were given to him by Edgar Thurston, Esq., of the Central 

 Museum, Madras, who collected them at Madras. 



Hertwig gives no characters by which this species can be distinguished from 



IHANS. KOy. DUB. SOC, N.S. VOL. IV., PART XXTI. 6 H 



