Mullusks. 8201 



incidents which are viewed and watched with absorbing interest. About one hundred 

 miles from Java Head it is nearly a calm. A huge tree, torn by some tempest from 

 its native forest, comes drifting by the ship, hoary with clustering Lepades and with 

 swimming-crabs clinging to it, as shipwrecked mariners to a raft. Anxious about the 

 barnacles, short-banded trunk-fish keep close alongside, making sudden onslaughts 

 upon the helpless Cirrhipedes; a shoal of bright green parrot-fish hover in the rear; 

 more lustrous still, three blue sharks dart about and around. la the distance a school 

 of brown Cetaceans, round-backed and long-nosed, comes coursing along, — vaulting 

 head downwards they wantonly pursue each other. Oo they go by fifties and by 

 hundreds, leaping, tumbling and dashing the spray about, so as to cause the mast- 

 headman to sing out from aloft, " Something like breakers on the starboard-bow." 

 The whole surface of the water is p.live with those fragile lesser forms of being which 

 coustilute of themselves a peculiar pelagiau faunula. You see the blue vesicle of 

 Physalia and the indigo disk of Porpita; the pellucid bells and globes and mushroom 

 bodies of the AcalephiE. and the glassy shrimps, Erichlbus and Alima. When, by 

 means of a towing-net, these are assembled together iu a vessel of sea-water the 

 interest is doubled, for now we begin to discern the erratic evolutions of the Ento- 

 moslraca, the steady progress of the small cerulean Poniia, and the skeleton-form 

 of long-eyed Leucifer. These move almost invisible among the equally pellucid 

 Sagittoe, true arrows darting, as their name implies, with rigid bodies through the 

 water. And now uprise with flapping wings the globose Cavolinee, and Styliola in 

 her tube-like shell. But what, amid these varied examples of oceanic life, is that tiny 

 floating bubble? It is nautiloid and yet no Nautilus, nor is there any keel to 

 constitute it an Atlanta. It is a recent Belerophina ! — Arthur Adams. 



Temperature of Snails. — M. J. B. Schnetzlev has been experimenting on the 

 temperature of the terrestrial mollusks, and has arrived at some interesting results, 

 which are recorded in the ' Bulletin Scienlifique.' He began with the Helix pomatia, 

 the large pale fawn-coloured snail, not uncommon in our lanes and woods, and which 

 is considered fine eating by epicures abroad. In April, 1861, when the air was 12°.l 

 cent., a snail of this kind was a little warmer, 12°.5. In June, when the air was 

 23°.7, the thermometer, when covered with the snail's foot, rose to 24°.7. A few days 

 later, when the thermometer stood at 18°.7, it rose on being introduced into the snail- 

 shell, and brought as near to the respiratory cavity as possible, to 20°. Irritating the 

 muscles of the animal gave a further rise of "To. In July a lively Helix pomatia, by 

 mere contact of its foot, raised the thermometer 2^ centigrade degrees.* Half an 

 hour later the air rose one degree, but the snail remained the same. In September, 

 after some snails had closed their shells for a month, a shower of rain came, and 

 although they were kept in a room they woke up, but their temperature did not exceed 

 that of the surrounding air. In January he placed two snails in the open air, having 

 removed their operculum. During the night the temperature fell to 2° cent., but 

 they were not injured ; on a subsequent night at 8° they froze and died. Slugs have 

 a lower temperature than snails. M. Schnelzler proposes to call these creatures 

 " animals of variable temperature," in contradistinction to mammals and birds, whose 

 temperature is generally more equal, if we except the changes which hybernating 

 Mammalia undergo. Mollusks may become colder than the air by evaporation from 



* A degree of Fahrenheit is equal to five-ninths of a degree of the centigrade scale. 

 VOL. XX. 3 c 



