224 



Dr. J. Gwyn Jeffreys on the [June 15, 



adapted to live on the bottom of deep seas — the most productive haul 

 having been the dredging in 1750 fathoms (No. 9, Davis Strait). This 

 furnished, among other well-known types, abundance of the small nauti- 

 loid Lituola canariensis, and peculiarly large and regular specimens of 

 the " spirilline " Trocliammina irregularis, the surface of which is finished 

 off with a smooth " plaster " composed of the finest sand-grains worked 

 up with abundance of ferruginous cement. — I shall now briefly notice the 

 more important novelties obtained in the ' Valorous ' dredgings. 



Eetaining, for the present, the general term Lituola for " tests " com- 

 posed of sand-grains firmly cemented together by phosphate of iron, and 

 imitating more or less closely the forms of calcareous-shelled genera, 

 I may specially notice the following as among its most conspicuous 

 types :— 



a. A large " nodosarijtie " Lituola, composed of a series of globular seg- 

 ments arranged in linear succession — the axis of growth being sometimes 

 nearly straight, sometimes regularly curved, sometimes irregular, and 

 the segments having no other connexion with each other than that which 

 is afforded by the small tubular neck which projects from each to be 

 received into the next. The wall of each segment, which is of very uni- 

 form thickness, is composed of extremely fine sand-grains, laid together 

 so as to constitute a beautifully smoothed surface both interiorly and 

 exteriorly; and the tubular neck has a perfectly circular orifice, sur- 

 rounded by a ring of somewhat deeper colour, which indicates that the 

 ferruginous cement is here present in greater quantity. The number and 

 size of the chambers varies in different specimens. The largest I have 

 met with, which is about 0*45 inch in length, has only four chambers — 

 the first having a diameter of about 0*08 inch, the second of 0*10 inch, 

 the third of 0*12 inch, and the fourth of 0-15 inch. Another, whose total 

 length would be about the same if the chambers were arranged in regular 

 linear series, has nine chambers — the diameter of the last or largest 

 chamber being somewhat less than that of the first or smallest in the pre- 

 ceding, whilst that of the first is only about 0*02 inch. 



h. Another " nodosarine," composed of segments of an ovoid shape, 

 the small end of each being prolonged into a tubular neck with a circular 

 orifice which is received into the next segment, and the prolonged neck 

 of the last segment forming the mouth. The total length of this usually 

 ranges between 0*4 and 0-7 inch, and the number of segments is commonly 

 from seven to ten ; its general form closely resembHng that of the calcareous- 

 shelled Lentalina guttifera, D'Orb., of which imusually large specimens, 

 attaining a length of 0*45 inch, occur in the same 1750 fathoms dredging. 

 But a series of small and very delicate forms, exactly similar in type, 

 also presents itself in this dredging, their total length ranging down- 

 wards from 0*25 to 0*15 inch. And in another series, distinguished by 

 the excess of the breadth over the length of the segments, most perfect 

 forms, composed of excessively minute sand-grains, present as many as 



