. Bulletin - United States National Museum. Science. BULLETIN 57, UNITED STATES NATIONAL MUSEUM. Genus RHYNCHISCUS Miller. 1S2:!. J'rohoscitlcd Simx, Siiuianiui I't Yt'Spcr(ili(iiuiin Spec. Nov., \\. Cil. (Not rrolKiscidca .J. (i. BrugitTt', ITDl.) ISCI. h'li!/iich(>ii!icl(ii-s Teters. Moiiatsl)tn-. k. inviiss. Akad. Wissenscli., lU'i-liu, p. 477. (Not Rliiiichoinjctciix Tseluuli. 1844-4(>.) 1878. Rlnj)K-hs<-!<]c(i ^lyix^^Vespert/Jio iKtso Wit'd. GcoiirdplvH' (JUtr'ihuthm.—The mainland of tropical America. Nvviher of forms.—Only one species of Rlnpu-lnscus is no
. Bulletin - United States National Museum. Science. BULLETIN 57, UNITED STATES NATIONAL MUSEUM. Genus RHYNCHISCUS Miller. 1S2:!. J'rohoscitlcd Simx, Siiuianiui I't Yt'Spcr(ili(iiuiin Spec. Nov., \\. Cil. (Not rrolKiscidca .J. (i. BrugitTt', ITDl.) ISCI. h'li!/iich(>ii!icl(ii-s Teters. Moiiatsl)tn-. k. inviiss. Akad. Wissenscli., lU'i-liu, p. 477. (Not Rliiiichoinjctciix Tseluuli. 1844-4(>.) 1878. Rlnj)K-hs<-!<]c(i ^lyix^^Vespert/Jio iKtso Wit'd. GcoiirdplvH' (JUtr'ihuthm.—The mainland of tropical America. Nvviher of forms.—Only one species of Rlnpu-lnscus is now known. Characters.—Dental fornnila : (57 1' '^"" Y=~^ m 3-3 o= 12 3. 1. -2-4567 3-3' 1 -V ' 2-2' 3 - Upper incisor minnte, simple, persistent, inserted in main axis of premaxillary and at extreme tip of bone, the teeth, therefore, converging. Lower incisors small, trifid. forming a continnous, slightly concave line betAveen canines. Canines and lower premolars as in EmhaUonura. Anterior iip])ei" premolar {i>)ir) nnnsually large, its crown sharply pointed and noticeably flat- tened laterally, the outline being nearly an isosceles triangle. First upper molar with conspicuous antero-external cusp separate from small parastyle. Hypocone of m^ and ^ ,„ „ rri - very distinct, subterete. Third upper Fig. 13.—Rhynchiscus naso. Adult MALE, escondido molar witli well-developcd metacone and RivER^ NICARAGUA. 50 ^j^ commissures. Lower molars all alike FROM Bluefields. x2. in form, the third merely smaller than the others, all the cusps normal. Skull (fig. 13) with rostrum somewhat more than half as long as brain case, and so deep posteriorly that the forehead forms scarcely any angle with u})per surface of rostrum. Lachrymal region slightly inflated. Premaxillaries short, very broad posteriorly, extending to upper surface of rostrum. Basisphenoicl pits deep, their outer border sharply defined; but on inner side the}^ merge into eac
Size: 1324px × 1887px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
