oct. 1768 MARINE ANIMALS 15 
and bones of fishes which this animal must continually 
swallow without separating them from the flesh. From the 
outside of its scales we took a small animal which seemed 
to be a louse (if I may so call it), as it certainly stuck to 
him, and preyed upon the juices which it extracted by 
suction, probably much to his disquiet: it proved to be 
Monoculus piscinus, Linn. Baster has given a figure of it in 
his “ Opera Subseciva,” but has by some unlucky accident 
mistaken the head for the tail. Inside the fish were also 
found two animals which preyed upon him; one Fasciola 
pelami, Mss., in his very flesh, though near the membrane 
which covers the intestines; the other Sipunculus piscium, 
Mss., in the stomach. 
2nd. This morning two swallows were about the ship, 
though we must now be sixty leagues at least from any land ; 
at night one of them was taken, and proved to be Hirundo 
domestica, Linn. 
4th. I went out in a boat and took Dagysa strwmosa, 
Medusa porpita, which we had before called azurea, Mimus 
volutator 1 and a Cimex, which runs upon the water here in the 
same manner as C. lacustris does in our ponds in England. 
Towards evening two small fish were taken under the stern ; 
they were following a shirt which was towing, and showed 
not the least signs of fear, so that they were taken with a 
landing-net without the smallest difficulty. They proved to 
be Balistes monoceros, Linn. 
7th. Went out in the boat, and took what is called by 
the seamen a Portuguese man-of-war, Holothuria physalis,’ 
Linn., also Medusa velella, Linn., Onidiwm spinosum, Mss., 
Diodon erinaceus, Mss., Dagysa vitrea, Mss., Helix ianthina, 
Linn., violacea, Mss., and Procellaria oceanica, Mss. The 
Holothuria proved to be one of the most beautiful 
sights I had ever seen; it consisted of a small bladder, in 
shape much like the air-bladder of a fish, from the 
bottom of which descended a number of strings of bright 
blue and red, some three or four feet in length; if touched, 
1 This cannot be identified. 
2 The Portuguese man-of-war is now known as Physalia, and is classed 
among the Celenterata. 
