150 Pelagian Mollusca collected on a [no. 2, new series, 



Beagle he alludes to a towing net of M bunting," but he does 

 not mention how it was kept open. Not having tried a net with a 

 wooden hoop, I cannot pronounce on their respective advantages, I 

 observed that with the iron hoop our net was generally half sub- 

 merged, and it would thus probably have more scope for the cap- 

 ture of specimens than a net with a wooden hoop, which would 

 oftener skim the surface without dipping sufficiently, but the strain 

 was very great with the iron hoop as we not unfrequently lost both 

 net and hoop. We generally examined our net every quarter of an 

 hour as we soon found that when it was left too long, its contents 

 were very apt to be damaged by friction. 



On the 8th of April in Lat. 29-32 N. Long. 18*56 W. we made 

 the first trial of the net, but the speed of the ship immediately tore it. 

 For the next two or three days we essayed with nets made of " gunny 

 bag," a kind of coarse brown cloth of open texture, but they retain- 

 ed too much water and owing to the dark color of the cloth it was 

 difficult to see if there was anything in the net ; finally we return- 

 ed to the use of white mosquito gauze, the only objection to which 

 was, that it too often required to be repaired or renewed. 



April 18th, Lat. 7*6 N. Long. 24*55 W * At night we pass- 

 ed a few PyrosomaSy these animals the most brilliant of noctilucent 

 molluscs, belong to the 6th Class or Ttjnicata. They are cylin- 

 drical, cartilaginous bodies, 3 or 4 inches long,open at one end,tuber- 

 culated, hyaline or almost transparent; they rise to the surface only 

 at night, and although but few were seen on this occasion, yet dur- 

 ing a former voyage, when near the same Lat. and Long, our ship 

 for eight successive nights passed through countless thousands of 

 them. They evidently floated a little below the surface ? as we could not 

 manage to enclose any in the net, but by means of several large 

 fish hooks tied together and dragged astern we were enabled to se- 

 cure two fine specimens for examination. When first taken in the 

 hand in the dark, they shone like molten metal, in color a pale but 



* Itmustbe borne in mind that the Latitudes and Longitudes mentioned, al« 

 •ways refer to the actual position of the ship at noon, but by referring to our 

 course traced on the accompanying chart, our position at any given time may be 

 inferred witb sufficient accuracy. 



