MR. ALDER ON THE MOLLUSCA. 181 
more nearly to the Scandinavian than to that of the south of 
England. The most interesting animal met with was the Zero 
formosa of Lovén, a curious and beautiful nudibranch of a genus 
new to Britain, but occurring on the coasts of Norway and 
Sweden. It was dredged in 26 fathoms off Holy Island, and is 
a valuable addition to the British fauna. A specimen of Stylifer 
Turtont was got in 15 fathoms within the Fern Islands. The 
rarity of this species is shewn by the fact that although numerous 
specimens of Hchinus esculentus and EH. neglectus were carefully 
searched, only a single Stylifer was obtained: it is usually found 
nestling among their spines, and, rare as it is on our coast, until 
lately, more specimens have been found here than in any other 
locality. ‘The shells got in this year’s dredging suggest nothing 
to add to the remarks of Mr. Mennell on their geological relations 
in last year’s Report. The following species were obtained :— 
MOLLUSCA. 
Of Holy Island. Durham Coast. 
CEPHALOPODA. 
Sepiola Atlantica, D’Ord. 1". This is probably the species 
named S. Rondeletii last year. 
GASTEROPODA. 
Trophon clathratus, Linn. i Dead shells. 
Fusus gracilis, Da Costa TC. 
propinquus, Alder 7, 
antiquus, Linn. T. P Small. 2 
Buccinum undatum, Linn. TC. *» The stout Coralline zone 
variety. 
Nassa incrassata, Will. 1. Dead. 
Mangelia teres, Yorbes vs Three or four dead speci- 
mens, 
linearis, Mont. r, 
Trevelyana, Zurt. 7. tr. 
turricula, Mont. 0. 
Cyprza Europea, Mont. r Dead. 
Natica Alderi, Forbes (N. 
nitida, F, and H.) Ce 7.C. 
Natica Montagui, For. TC. 
Velutina levigata, Zinn, %. ”, 
Trichotropis borealis, Brod. r.c. Three fine living specimens, 
the rest dead. 
Stylifer Turtoni, Flem. r One specimen. 
