272 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



centre to angles of each scale, in adult armed simply with tubercles, 

 nine to ten, in longitudinal series from gill-opening to tail, eight in 

 median line of ventral surftice, eight between ventral keel and angle 

 of back. Posterior dorsal scute unarmed. 



Branchial aperture oblique, its length greater than the diameter of 

 the eye, descending before the base of the pectoral. Fins obtusely 

 rounded. Pectoral equaling in length. Caudal of moderate length and 

 rounded. 



Eadial formula D, 10, A. 10, P. 12. 



Color : The color of living individuals is thus recorded in my Bermuda 

 note-book: — "Dark-brown, thickly studded with circular sx)ots of yel- 

 lowish white, each about two lines in diameter ; the position of these spots 

 appears to have no relation to the shape of the plates of the carapace. 

 Ventral surface lighter and spotless. The epidermis is often abraded 

 leaving the shell uniform tawny- white. The lips, bases of the fins, and 

 tail-stem are brown like the ground color of the body." In dried speci- 

 mens the epidermis dries and loses its color, and the shell shows through 

 with a lighter shade. Giinther states that the lips, roots of the fins, 

 root of the tail, and tip of the caudal are black. This I have not ob- 

 served. 



The largest individuals seen by me measured about 265 millimetres 

 in length, but these were quite unusual in size. 



The Cuckold is common throughout the West Indies, and has been 

 found south to Bahia, while, to the north, it is carried by the Gulf 

 Stream as far as the Bermudas. Its limits of distribution are more 

 closely restricted to the Caribbean Sea and the neighboring waters than 

 those of any other species in the genus. 



It is recorded that the crew of Columbus, on their first voyage, in 

 1492, while at anchor on the coast of Cuba, captured a fish which "was 

 like a swine, all covered with a very hard skin, no part whereof was soft 

 but the tail," which was probably one of the Ostracions. 



Little can be said in reference to its habits, except that it is sluggish 

 and lives close to the bottom, where it probably feeds upon hydroids 

 ascidians, and other soft-bodied animals. This is somewhat conjectural 

 for no one has ever taken the pains to examine the stomach contents of 

 any member of the genus, but it is not very hazardous to make this sur- 

 mise, for the sluggish movements of the Trunk-fish would not permit it 

 to pursue active living prey, while its small, weak teeth are thoroughly 

 unsuitable for feeding upon shells and barnacles. 



The method of locomotion in this and other members of the genus 

 Ostracion is very peculiar. When in Bermuda, in 1872, I had two of 

 them for a time in my aquarium, and had an excellent opportunity of 

 observing the movements of their fins. 



The rigid shell prevents any flexure of the body, the only parts with 

 power of independent motion being the lips, the dorsal and anal fins, 

 and the stem of the tail. These protrude through openings in the cara- 



