420 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



8. Tetrapturus Lessonii, Canestrini. 



ll'trajdcrus Lessonii, Canestrixi, Arch. Zool. 1861, i, p. 259, pi. vii. — LiJTKEX, 

 11. c— Day, 11. c. 



This species, described by Canestrini from the Mediterranean, is re- 

 feiTe<l by Liitlien to the general cosmopolitan type, of which T. iadicus 

 and T. Herschelii are the representatives. 



Descriptive notes on the American spear-fish, Tetrapturus 



ALBIDUS. 



The following description was drawn up from a fine specimen of the 

 spear-fish taken at Block Island, E. I., in ISTo: 



A male fish of 2,l50"™ (84.646 inches), ordinary size. 



Body elongated, nape elevated, bringing' the greatest height over the 

 opercnlum (10.27 inches). At the point of the pectoral the height is 

 nine-elevenths of that at the operculum (8.4 inches), and is contained 

 about 10 times in total length. 



The head from extremity of lower jaw is contained in the total length 

 4 times (21.161 inches). The eye is situated midway between operculum 

 margin and tip of lower jaw. The length of the bill beyond lower jaw 

 equals greatest height of head. Palatines with a narrow band of rough 

 denticulations. Asperities on the lower jaw. Bill extremely hard, espe- 

 cially at i ts extremity ; its form is depressed, its edges rounded, its height 

 greater than half its width. Preoperculum situated far back; com- 

 mences midway between the eye and the opercular margin. The other 

 opercular bones are not visible in fresh specimen. 



Lateral line marked by a series of minute apertures on a continuous 

 band, connected at tlie top of operculum; continues backward in a 

 straiglit line for a short distance, then bends downward and reaches the 

 middle line of the body at the point ol the pectoral. Scales bony, 

 linear, absent from the head, except on the cheeks. Those of lateral 

 line not pierced. All the scales covered by epidermis. 



Br. 7 ; D. 3, 30-6; A. 2, 13-6; P. 19 ; V. 1, 4; C. 12. 



All the rays osseous, not articulated ; those indicated as osseous are 

 only distinguished from the others by their terminating in a point, 

 which is not free. The others are flattened towards the extremity and 

 frayed at the ends. The two first anal and three first dorsal rays are 

 ossified to each other and upon the ray behind them, so that they appear 

 to sight and touch as if only a single ray. Dissection shows that the 

 first dorsal is very small (20'""') ; second, 2^ times as high (50'""'); third, 

 115"""; the fourth twice as long. The same in anal. First, 30™"'; 

 second, 70"'">; third like fourth dorsal in form. These fins are lor the 

 most part hidden in the furrows, and their last rays are extremely short, 

 so that it is necessary to lay them bare by dissection. 



First ray of second dorsal and second anal flat and striated; these 

 fins are crenated. The fourth of arst dorsal and third of first anal 

 tou( h the summits of the fins, which are slightly rounded. 



