86 report— 1877. 



be placed in the latter category ; and the old proverb, " noscitur ex sociis," will 

 apply to mollusks as well as to men. Teredo may have been littoral or have come 

 from floating wood. Not a single species of Leda, Pecchiolia (or Verticordid), 

 Near a, not one of the Solenoconchia nor of the Bulla family occurs in the upper or 

 white Chalk, although they now inhabit the deep-sea ooze and especially charac- 

 terize the modern deposit. 



But Nautilus and Spirula are believed by some to be deep-water forms. This 

 must be a mistake. Although the animal of that common species Nautilus pom- 

 pilius has rarely been met with, the shells are often found on beaches in the Indian 

 Ocean and South Pacific; and I am not aware of any instance of a deep-water 

 mollusk being cast ashore. It is not likely. Buniphius (the "Plinius Indicus "), 

 in his ' Amboinsche Rariteitkarner,' or Cabinet of the Curiosities of Amboyna, 

 1705, has given an interesting account of the habits of the Pearly Nautilus, a trans- 

 lation of which I will copy from the admirable monograph of Professor Owen : — 

 " AVhen the Nautilus floats on the water, he puts out his head and all his tentacles, 

 and spreads them upon the water, with the poop of the shell above water ; but at the 

 bottom he creeps in the reverse position, with his boat above him, and with his head 

 and tentacles upon the ground, making a tolerably quick progress. He keeps himself 

 chiefly upon the ground, creeping also sometimes into the nets of the fishermen ; but 

 after a storm, as the weather becomes calm, they are seen in troops, floating on the 

 water, being driven up by the agitation of the waves. This sailing, however, is 

 not of long continuance, for having taken in all their tentacles, they upset their 

 boat, and so return to the bottom." 



As to the Spirula, the old Dutch naturalist remarked that it attaches itself to 

 the rocks, and is thrown up on the beach when the north wind blows. Peron 

 found the first living specimen in Australia ; Mr. Percy Earl obtained one on the 

 coast of New Zealand ; the late Sir Edward Belcher another in the Indian Archi- 

 pelago ; Mr. Bennett got one off Timor ; and an imperfect specimen was procured 

 m the ' Challenger ' Expedition. I was favoured, in January 1875, by Mr. J. 

 Tyerman, of Tregony, sending for my inspection a perfect specimen of Spirula 

 aus/ralis and one of Aryonauta gondola in spirit of wine, with a memorandum 

 that " the Spirula and Argonauta were taken by a friend while dredging or, rather, 

 skimming for Pteropods in the Persian Gulf." Mr. Tyerman added that other live 

 specimens of the Spirula were captured at the same time. Sir Lewis Pelly informs 

 me that the Persian Gulf is nowhere deeper than between 40 and 50 fathoms. 

 Spirula has apparently the same habit as species of Loligo and allied genera, in 

 occasionally frequenting the surface of the sea. The shells of S. australis are 

 thrown up in considerable numbers on every beach in the North Atlantic, having 

 been wafted northwards by winds and the equatorial cm-rent or so-called " Gulf 

 Stream." 



Assuming, therefore, that the usual habitat of Mollusca in past epochs did not 

 differ from that of recent Mollusca of the same kind, I think we may safely con- 

 clude that the shells of the Cretaceous system, or, more strictly, the Upper Chalk, 

 belonged to shallow and not deep-water Mollusca. 



Mr. Woodward tells me that the Chalk Crustacea are also shallow-water forms. 

 The white chalk is in many places principally composed of Globiyerinee, Orbulhuc, 

 and coccoliths or coccospheres, all of which inhabit at present the surface of the 

 sea. According to Dr. "Wallich, Gldbigerina is found in all latitudes and at all 

 depths, ranging from 50 to 3000 fathoms *. Mr. Parker and Prof. Eupert Jones 

 (first-rate authorities on the Foraminifera) admit that Orbulina and Globitjerina 

 are " occasionally found in shallow water "f. 



I cannot identify a single species of the Cretaceous Mollusca as now living or 

 recent. All of them are evidently tropical forms. One of the Cretaceous species, 

 indeed, Terebratula striata, Wahlenberg, has been supposed by some palaeon- 

 tologists to be identical with T. caput-serpentis, the latter of which has a range of 

 bathymetrical distribution from low-water mark to 808 fathoms ; its geographical 

 extension is equally great, and it has also not a slight amount of variation in 



* North-Atlantic Sea-bed, p. 137. 



t Quart. Journ, Geol. Soc. vol. xvi. p. 279. 



