GILBERT AND S TAUKS — I'ISII KS OF PANAMA liAV 9 



Tills species is known as yet only iVdin iIk; Hay of Panama. Like O. caVifor- 

 n'lciix, from wiiidi it dilleis widely in other respects, it has th(! yonnji allaclied to the 

 oviihut liv a placenla. Phe three specimens ohtained hy this expedition are all 

 females; oni; of tliein eniilains well de\(li)|M(| ynimi;'. 



4. Galeocerdo tigrinus MulUu- <f- llenlc 



Recorded from I'anama hy .loidan and liollman (l.SS!», p. 17!)), their speci- 

 men having- been collected hy the "Ali»atross." The s|>ccies was not seen by the 

 aulhuis. 



5. Carcharias aethalorus Jordun .f- Gilhcrl. 



Abniidanl at Panama, where it is used as food lhon,i:;li nut lii.i;hly prized. 

 Small specimens only were seen. In a male about !*()cm. lonj:;, the claspers are very 

 small, not reaching margin of ventrals. The teeth of both jaws are distinctly serrate 

 in these young examples, the serrie growing coarser towards base, equally present 

 on the two margins. The interspace between dorsals is 5 to (i times base of 

 second dorsal (excluding the Heshy ridge before lin), and the base of anal consider- 

 ably less than (1| in) its distance from caudal. Fn other respects the Panama 

 specimens answer well the original desciiplion. 



6. Carcharias velox (Gilbert). 



Pi.ATF. I, Fi<:. :!. 



Carcharhins velo.w Cilhekt, Jordax iK: Kvermann, 1898, p. 2747. 



Distin.y-uishaljle from other known sharks of the Pacific coast of .Xnierica by the exxessively 

 lony, sle-nder, acute snout, tlie slender body, and the very lono caudal tin. 



I'rtcM-.i! iiortion of snout slinhtiy more than i '^ times width of mouth, 5 times distance 

 between nostrils, if, times width of snout opposite outer angles of nostrils, I J times interorbital 

 width, 2 ;J times distance from chin to line joining angles of mouth. Nostrils transverse in position, 

 the inner ant^le nearer nuiuih tlian lip of snout i)y a distance slii^htly less than length of nostril. Front 

 of eye equidistant from nostril and front of mouth, the middle of eye nearer angle of mouth than 

 nostril; diameter of eye less than nostril, slightly more than half longest gill-slit. Snout very porous. 

 Fokis at angle of mouth slightly long.r llian usual. (".ill-slits rather wide, the mi(klle slit if times 

 diameter of orbit. 



Teeth of lower jaw very narrow, erect, very minutely serrulate, apjjearing entire except with 

 the lens. The species thus rejiresents a transition between Carcharias and the alleged genus 

 Hvpoprion. Teeth in upper jaw very oblicpie, witle at l)ase, with a deep notch on outer margin, the 

 terminal cusp rather narrowly triangular. 



Pectoral broadly falcate, the anterior margin convex, the distal edge concave, lx)th angles 

 rounded. Tip of pectoral reaching a short distance beyond base of first dors;il. Anterior margin 

 of i)LCtoral 2 1 times the posterior (inner) margin, about \\ times the distal edge. First dorsal 

 inserted about the diameter of orbit behind a vertical from axil of pectoral; nearer iiectoral, therefore, 

 than ventral. The anterior margin is concave basally, convex on distal half, the anterior angle 

 rounded. The free margin is concave, largely owing to the much produced acute posterior lobe. 

 The vertical height exceeds the length of the base; the anterior lobe very high, extending beyond 

 tiji of posterior when the fin is declined, equaling \ leng:th of anterior margin of iiectoral. Posterior 

 margin of first dorsiil 3J in the anterior margin. Base of first dorsal contained 2\ times in interspace 



