ON THE FRENCH DEEP-SEA EXPLORATION IN THE BAT OF BISCAY. 381 



that of the Atlantic ooze ; and this mud has probably accumulated from 

 untold ages by the incessant efflux of the Gironde, the Adour, and nume- 

 rous other rivers and streams into the Bay of Biscay. As may be supposed, 

 the fauna which inhabits such mud is very scanty ; and it required a con- 

 siderable amount of patience and perseverance to extract even a few 

 organisms from the unpromising material. No wonder that Dr. Carpenter 

 ■was discouraged, as a zoologist, by what he termed ' the singular barren- 

 ness of this deposit in regard to animal life,' when he described the 

 Mediterranean cruise of the Porcupine in 1870. 



Within a few days after the retui'n of the expedition, Prof. A. Milne- 

 Edwards presented to the Academy of Sciences at Paris a preliminary 

 report of the zoological results of the expedition, which was published in 

 the Journal Officiel de la Bepublique Franq.aise as well as in the Comptes 

 Hendus. As most of the departments of the marine Invertebrata have 

 been so fully and carefully treated by him in this Report, I will content 

 myself with a few supplementary remarks as to the Mollusca, which 

 especially engaged my attention during the cruise. At the request of 

 Dr. Fischer, who will undertake this department, and with the sanction 

 of the President, I was entrusted with all the more critical specimens of 

 Mollusca ; and these specimens I have now cleaned, assorted, and com- 

 pared with my ow^n collection from the Porcupine Expedition of 1870 on 

 the western coasts of Spain and Portugal. I subjoin a complete list of 

 the Travailleur Mollusca, distinguishing in separate columns those 

 species which are Porcupine, those which were previously known to me 

 from Norway or the Mediterranean only, and those which I consider 

 new to science. The total number of the species in this list is 198, 

 out of which 169 are Porcupine, nine only appear to be exclusively 

 northern, one exclusively southern or Mediterranean, and seventeen 

 new to science. Two of the Porcupine species are northern also. The 

 results, especially in the last-mentioned category, are most noteworthy. 

 They serve to show how little we know of the deep-water Mollusca, 

 ■when we reflect that the area of the sea-bed lately explored, in a short 

 period of time and in a necessarily cursory manner, is but a very small 

 corner of the Atlantic, and that it would take many years to complete 

 the exploration so auspiciously commenced. The space traversed by 

 the dredge during this cruise represents probably much less than a ten- 

 thousandth part of the sea-bed lying between Cap Breton and Cap 

 Peuas : and our means of exploration by the dredge are by no means satis- 

 factory, pai-ticularly on muddy ground, of which the deep water zone is 

 mainly composed. Instead of our being able to scrape a few inches of the 

 surface of the sea-bed at considerable depths, so as to collect in the dredge 

 all the animals which inhabit the superficial layer, we find too often, to 

 our disappointment, that the dredge when it reaches the bottom sinks into 

 the mud from its own weight and from the momentum given to it by the 

 motion of the ship, and that it then acts as a subsoil plough and not as a 

 scraper. I must ask one of my engineering friends to devise some instru- 

 ment more efficient than the modern dredge. 



Although it cannot be positively stated that the abyssal zone, or even 

 the benthal zone, is inhabited by species of Mollusca peculiar to it, some 

 species observed by me during the preparatory excursion to Cap Breton 

 and the Travailleur cruise bear out the statement to some extent. For 

 instance, Nuctda nitida, Dischides bijissus, Rissoa ahyssicola (a now inap- 

 propriate specific name), and Defrancia decussafa occurred only in the 



