4 ENGLAND TO RIO DE JANEIRO CHAP, i 



animal, by the help of which they swim with some degree 

 of activity when separated from each other. Several sorts 

 are most generally seen joined together, gemmce more par- 

 ticularly, which adhere in irregularly-shaped clusters of some 

 hundreds ; in the midst of these were generally found a few 

 specimens of cornuta, from which circumstance we may 

 judge that they are very nearly allied. It seems singular 

 that no naturalist should have taken notice of these animals, 

 as they abound so much where the ship now is, not twenty 

 leagues from the coast of Spain. From hence, however, 

 great hopes may be formed that the inhabitants of the deep 

 have been but little examined, and as Dr. Solander and my- 

 self will have probably greater opportunity in the course of 

 this voyage than any one before us, it is a very encouraging 

 circumstance that so large a field of natural history has 

 remained almost untrod until now, and that we may be 

 able from this circumstance alone (almost unthought of 

 when we embarked in the undertaking) to add considerable 

 lights to the science which we so eagerly pursue. 



This evening a large quantity of Carcinium opalinum, 

 which may be called the opal insect, came under the ship's 

 stern, making the very sea appear of uncommon beauty, their 

 colours appearing with vast brightness even at the depth of 

 two or three fathoms, though they are not more than three 

 lines long and one broad. 



*lt~h. On examining the Dagysce which were taken yester- 

 day several small animals were found lodged in the hollow 

 parts of their bodies, and some in the very substance of 

 their flesh, which seems to be their food, as many of the 

 Dagysce were full of scars, which had undoubtedly been the 

 lodgment of these animals some time before. Upon a 

 minute inspection they proved to be animals not to be 

 classed under Linnseus's genera, though nearly related to 

 Oniscus, from which circumstance the name of Onidium 

 was given to the new genus, and to them was added an 

 animal taken on the 28th of August, and mentioned by 

 the name of Oniscus macrophthalmus. 



In one particular these insects differ from any hitherto 



