1882.] 'lightning' AND 'PORCUI'INk' KXPEDITIONS. 673 



He says it is " not aa Aciueid," and would place it near Capuhs ; 

 but he qualities his remark by saying that " it is barely possible it 

 may be a Cocculina." He is an uuquestiouably good authority ou 

 this as well as other departmeuts of the MoUusca ; aad I venture 

 with much hesitation to differ from him. 



Addisonia eccentros, (excentrica) Tiberi. 



Gadinia excentrica, Tib. in Journ. Conch, vi. p. 37, pi. ii. f. 6. 



'Porcupine' Exp. 1870: Atl. St. 16; Med. Adventure Bank. 

 Two specimens. 



Distribution. Coral-fishery, Sardinia (TifierO ; a single specimen, 

 with Gadinia gussoni. 



I have made a slight change in the specific name by substituting 

 a classical word for one which is not Latin. 



This remarkable shell appears to be the Addisonia paradoxa of Dall 

 (Proc. U.S. Nat. Mus. 1882, p. 405), which was dredged by 

 Verrill off the New-England coast in 69-130 fathoms. Dall long 

 ago pointed out that Tiberi' s species was not a Gadinia. Tiberi's G. 

 compressa (recent and fossil), of which through his kindness I possess 

 specimens, is certainly a species of Lepetella, Verrill, and comes 

 near L. tubicola, which has been lately found by G. O. Sars on 

 the western coasts of Norway. Addisonia appears to be allied to 

 Pilidium. See the above-cited ' Proceedings of the United-States 

 National Museum ' for Call's excellent and elaborate paper on the 

 families CocculinidcB and Addisoniidce, consisting of the genera 

 Cocculina and Addisonia. The present species is not the Patella 

 excentrica of Sandberger from the Mayence Basin. 



Although the genera XJinbrella and Tylodina (which are closely 

 allied) have a patelhform shell, there is a peculiarity in that respect 

 which connects them with Aplysia and the Nudibranchs, viz. in the 

 spiral and heterostrophe nucleus. Tylodina dueheni of Loven occurred 

 at Stations 24 and 27 of the ' Porcupine' Atlantic dredgingsin 1870. 

 It seems rather strange that M. Gaston Moquin-Tandon, in his long 

 and studiously exhaustive memoir on the Umbrella of the Mediter- 

 ranean, did not notice this peculiarity, nor even assign or propose 

 any place for that genus in the classification of the Mollusca, while 

 he freely criticised all previous writers ou the anatomy of the animal. 



^ 1. Propilidium ancyloides, Forbes. 



Patella ancyloides, Forb. in Ann. Nat. Hist. v. p. 108, pi. ii. f. 16. 



Propilidium ancyloide, B. C. iii. p. 254, pi. vi. f. 1 ; (P. ancyloides) 

 V. p. 200, pi. Iviii. f. 7. 



' Lightning ' Exp., St. h. 



•Porcupine' Exp. 1869 : St. 1, 6, 13, 14, 19. 1870 : Atl. 16, 

 17, 1 7a; Med. Adventure Bank. 



Distribution. 'Valorous' Exp., Loffoden I. to Galway coast, 

 Kimmeridge B. Dorset {Pleydell) 1, Naples {Acton), Trapaui, Sicily 

 (Seguenza) ; 10-1450 fms. 



Fossil. Pliocene: Sicily. Post-tertiary: Christiania; 30-100 ft. 



Rostrisepta parva of Seguenza. 



46* 



