EEPORT ON THE GASTEROPODA. 581 



This is a much stronger shell than Clthna tcnella, JefFr., usually is ; in form it is much higher 

 in the spire, and narrower in proportion to breadth ; the whorls are much more compressed, and the 

 narrow sharply impressed suture is much less deep ; the mouth is oval, not round, and the sculpture 

 of the surface is very different from the hyaline gloss and texture of that other. It is unfortunate 

 that the apex, which is so characteristic a feature in Clthna tcnella, is broken in the Challenger 

 specimen. 



Dr Gwyn Jeffreys, in his Moll. "Lightning" and "Porcupine," Proc. Zool. Soc. Lond., 1883, p. 11 1, 

 says that this species is Clthna tcnella, Jeffr., var. costulata. That is a varietal name plainly not wanted if 

 my Clthna margarltifcra is only a variety. For so reckoning it he assigns no reason. It had probably 

 escaped his memory that it was on his recommendation, with considerable hesitation on my part, that 

 the species was described as new. Published as new it is safer so to leave it. From Pernambuco 

 to the North Pacific is a step which, unbroken, is somewhat long unless one is very sure of one's 

 footing, and as regards that certainty, the fact that when the Pacific shell was under careful exami- 

 nation and full comparison with various forms of Cithna tcnella, the final estimate of us both, and 

 of Dr Jeffreys more decidedly than of myself, was that it should be held as distinct, must go for very 

 much. 



4. Fossarus, Gray, .1840. 



Species. 



1. Fossarus amhiguus, Linne. 2. Fossarus cereus, Wats. 



1. Fossarus amhiguus (Linne). 



Le Fossar, Adanson, Senegal, p. 173, pi. xiii. fig. 1. 

 Helix ambigua, Linne, Syst. Nat. (ed. 12), p. 1251. No. 714. 

 „ ,, Dillwyn, Catalogue, vol. ii. p. 973, sp. 191. 



„ ,, Wood, Index Test, p. 176, pi. xxxv. fig. 188. 



Fossarus Adansonii, Philippi, Enumeratio Moll. Sicil., vol. ii. p. 147, pi. xxv. fig. 1. 

 Helix ambigua, Hanley, Ipsa Linn. Conch., pp. 391, 541. 



Fossarus amhiguus, Philippi, Conch. Cab. (ed. Kiister), p. 12, sp. 1, pi. i. figs. 1-8. 

 Fossar Adansoni, McAndrew, Distrib. Moll. N. Atlantic, p. 30. 

 Fossarus ambiguus, Fischer, Genre Fossarus, Journ. de conch., 1867, vol xii. p. 256. 



,, „ Weinkauff, Conch Mittelmeer., vol. ii. p. 267, sp. 1. 



,, „ Aradas and Benoit, Conch. Mar. Sicil., p. 181, No. 483. 



„ ,, Monterosato, Enumerazione, p. 23. 



Station 113a. September 2, 1873. , Lat. 3° 47' S., long. 32° 24' 30" W. Anchorage 

 off Fernando-Noronha. 7 to 25 fathoms. Volcanic sand and gravel. 



Station 122. September 10, 1873. Lat. 9° 5' to 9° 10' S., long. 34° 49' to 34° 53' W. 

 Off Pernambuco. 350 fathoms. Red mud. 



Habitat. — Senegal (Adanson) ; Canaries, Madeira, and Azores (McAndrew) ; Mediter- 

 ranean (Philippi). 



Fossil. — In the Post-Tertiary beds of Sicily (Philippi). 



