12 CAMl-oliNIA ACADEMY OF Sl'IENCES 



Tfi'th in npiHT jaw brtiadly trian.i;iilar, (iMiiiur, tin- antfiior vi\y,v ni-ntly coiivrx, ihr iniUT 

 Hfiitly concavi- ami often willi a sliijlil nutch tlivulinj^ tlic niarj;in into cciiial jxirts. Tt-itli in lower 

 j.-«w erect, narrowly lanceolate from a broatl base. All the teeth are stronjjly serrate on Im.iIi mars^jins. 



IVotorals lonjj anil wide, concave i)osteriorly, hence a|>|K'arinjj; falcate, their tips extendinj^ 

 slightly iK-yond kise of first dors;il. Both angles are broailly rounded. ri)per niarjiin of jxctorals 

 3i to 3i times lower marjjin, and i J to ij times the [xisterior marjjin; its len.i;th etjuals that of luad 

 in advance of first i^ill-slit. A line joininjj; a.xil of |M'ctorals pass<-s in front of origin of first dors.il a 

 di.stance ei|ualinj; iliaineler of orbit. Hase of first dorsal contained i^ to i!, times in anti-rior niari;in 

 of fin, and ij or ij times in the intersp;ice Ix-tweeii dorsals.. l'|)i)er margin comavi-, llu- jxjslerior imi 

 little |)r(Kliiced, contained 35 to ,^J times in anterior margin. .Second dorsil inserted well in advance 

 of anal, the lenj^th of its base contained 2\ to 2'^ times in base of first dorsal. 4I to 4^* times in the 

 inters|wce, i-| to il times in its distance from front of ciudil |iit. rostirior lol)e of .second dorsal 

 extends nearly half-way to oriii;in of ii|)per caudal loi)e. l-'ront of anal under end of first third of 

 ilors;il Ixise, the two fins nearly eipial in leiimth, the anal |K'rhaps sli,i;htiy the longer. Mari^in of anal 

 much more dee])ly concave. Distance from anal to orii^in of lower caudal lobe contained 1 I, limes in 

 distance from .second dorsal to orit;in of u])|K'r caudal lobe. Caudal slitihtly exceedini; j liie total 

 Ieni;th:the lower lobe with rounded ans,de apiK-arinj^; l>lunlly falcate, ct)ntained 2| times in upper lobe. 



Color uniform lijjht blue or bluish sray above, white below. Caudal anil second dorsal i>iack 

 margineil; the lower caudal lobe anil ilislal half of ]x-ctoral lariiely blackish. 



This species is well known lliough not abiuuliint at Panama, and is more liij;lily 

 prizeil as food than other sharks. It appeared in the market on two occasions during 

 the stay of the expedition, and three specimens were preserved, measiirinti fntm !(2 

 to 05 cm. Two of these are males with the claspcrs quite undeveloped, not nearly 

 reaching margin of veiitrals. The species is said to ii^ach a large size. 



('. nznreits is extremely near C. nicai-ar/nenaif^, from Lake Nicaragua and its 

 outlet, the San Juan River. Dr. Jordan has kindly conijiared the aiK)ve description 

 with a specimen of C. nicnraguensis (No. 8091;}) in the United States National 

 MuseniM. The latter has a longer and wider snout, the lengtii of which is eoutained 

 11 in its preoral portion, its width opposite the nostrils equaling the distance from 

 the angle of the mouth to the third gill-slit. The base of the first dorsal is I tlie 

 interspace between dor.sals, and the base of the second dorsal is contained 2.', times 

 in the first. The lower caudal lobe is contained 2s in the upper lobe. Tiic iicctoral 

 is but faintly dusky. These differences are not great, liut tin ic lias been no 

 opi>ortunity to make a direct comparison. Tu view of the exceptional distriliulion 

 of C. )uc(irit(/ue)isix, known only from fresh waters, which belong to the Atlantic 

 slope, it has not been thought wi.se to make the identification. 



9. Scoliodon longurio Jurdmi <£• Gilbert. 



Aitundant ,'it Panama, where six speciiuens were (ilitained. Tlic Icngtii of (he 

 base of the first dorsal is contained 2J to nearly 3 times in the interspace between 

 dorsals, not 21 times, as stated by Jordan & Evermann (l.SOC), p. 42). The teeth 

 are not at all serrate in the Panama specimens; the thin margin is .sometiiues gently 

 sinuate, but never toothed. 



