{ 883 a Zoölogy, 799 
Mollusks —The deep-sea mollusks are still engaging the atten- 
tion of malacologists. From Mr. Gwyn Jeffreys we have re- 
ceived a recent paper on the mollusks of the “Lightning” and 
“Porcupine” expeditions, in which he gives the results of com- 
parison of these shells with subappennine and Sicilian tertiary 
shells; teaching first, the exact concordance of so many species in 
their fossil and recent state, notwithstanding the lapse of the enor- 
mous and incalculable time which has intervened, and second, 
the extensive changes which have taken place during the same 
period between the depth of the ocean and the height of land in 
the North Atlantic area. In the Linnzan Society’s journal ap- 
pears parts xv and xvi of Rev. R. B. Watson’s Mollusca of the 
Challenger expedition. 
crystalline spheres. The eye is situated on the terminal process 
of the brain, and the optic nerves proceeding from it skirt the 
outer surface of the crystalline sphere and penetrate it near the 
hinder margin. This eye, therefore, may be considered as com- 
posed of three simple eyes, placed anterior to the brain, with 
reversed optical bacilli, and brought so close together that their 
Pigmented or choroid layers are combined into a single ‘mass. 
The eyes of the Chetognaths, though paired, have a similar 
structure, and certain Planarians have eyes like one of the simple 
eyes that are united in the median eye of the Crustacea. 
Mprey, according to M. 
sinning of July deposited its ova and regained the sea, which it left 
