CHAP. n.J THE CRUISE OF THE ' LIGHTNING: 75 



parent clam, Pecten vitreus, CHEMNITZ. Holtenia 

 extends from the Butt of the Lews to Gibraltar, in 

 from 500 to 1,000 fathoms. Mr. Saville Kent, 

 dredging in Mr. Marshall Hall's yacht 'Norna,' found 

 a singular variety off the coast of Portugal, which 

 from its flatter, more hemispherical form, and more 

 rigid anchoring spicules, probably inhabits a firmer 

 medium. 1 



As might be expected, the Atlantic ooze of this 

 station, rich in rhizopods giving an ample supply of 

 food, and with a comparatively mild climate, yielded 

 many living forms belonging to various orders. Along 

 with Globigerince and other small forms there were 

 many large rhizopods, among them Rhabdammina 

 abyssorum, SARS, a singularly regular triradiate sandy 

 form of a bright orange colour, and very hard ; from 

 analyses made by Dr. Williamson at the request 

 of Dr. Carpenter, its hardness is apparently owing to 

 , the cement employed by the animal in the construc- 

 tion of its case containing phosphate of iron, the only 

 instance of the use of this substance for such a 

 purpose of which we are yet aware : Astrorhiza 

 limicola, SANDAHL, a large irregularly -formed rhizo- 

 pod with a soft test of mud and sand : many large 

 Cornuspirce and Textularice, and large JBi- and Tri- 

 loculince and other miliolines : a few zoophytes, and 

 especially common the curious sea-pen Kophobelem- 

 mon mulleri, SARS, and the fine branching coral, 



1 On the Hexactinellidse, or Hexradiate Spiculed Silicious Sponges, 

 taken in the ' Norna ' Expedition off the coast of Portugal ; with 

 Description of New Species and Revision of the Order. By W. Saville 

 Kent, F.L.S., F.R.M.S., of the Geological Department, British 

 Museum. (Monthly Microscopic Journal, November 1st, 1870.) 



