TIIK IJATUACIIIA OF NORTM AMEllICA. 



22;j 



inactive lite (MHisoqiicnt on imriiNili(! liabitH. Tim waine result lias l)o- 

 rallcn till; Ijace'itiliaii lainily Aiiipliisbiciiiila': and the, Opiiidian t'atiiily 

 ol T.vpliIopiUa!. Iloth of tlK'.so art', like the Ca'ciliida', paiaisltlc in ants' 

 nests, and holli have become nearly blind and have lost their or}j;ans of 

 l>ro;>ression, whether limbs or abdominal scales. To aid them in \\\i\'n 

 darlv habitat ;i pecidiar tentacle has been developed in tiiis tamily, 

 which issues from ii canal of the maxillary bone. This canal passes 

 from the orbit, and the tt>ntacle which oe(ri)pi<>s it is fnrnishe<l with a 

 iniisclu and nerve (Weidersheiin). It is ])robably homologous with the 

 " l)aiancer" of the urodelous larva, which sometinu'S j)ersists as a non- 

 retractile tentacle in s»'veral «»f the species of the salamandiine yenns 

 Speleipes. 



The t'a'ciliida^ have been divided into a nnnd)er of jjenera by IVters. 

 The presence or absence of minute scales defines some of these, and 

 tlie form and position of the tenta(!ular openinj,' others, 8onu! of the 

 latter do not appt'ar to the writ<?r to be well founded. 



No species of the Ca'ciliida* enters the ycof^iaphical boundaries of the 

 nearctic realm. 



(Mate* 11 represents the skull and sonu> vertebne of the Clitlnnurpcton 

 iiiidstinctnm, 11. »>V^ L., si representative of the family from IJrazil. 



TIIA( IIVSroM.VTA. 



Vomeropalatiiu^ bones wantin;;. Supraoccipitals, intercalaria, ami 

 liasioc(tipitals wantinjf. Maxillary ijones wantin,i,^ I'ropodial bones not 

 foiissilied; cau<lal vertebra' distinct. 



This order, which was projiosed by Miiller, has but few liviny; repre- 

 sentatives, nor has paleontolo^'y disclosed with certainty any extinct 

 ones. The liinf^e of its variation beinjif thus unknown, I conline my- 

 self chieliy to a discussion of the characters of the only family which 

 it contains, the Sirenida'. The order is distinjiuislied, as above indi- 

 (Mted, by the absence of many bones of tins skull usual in veitebrata 

 ami IJatrachia — a result which is apparently dui! to a. lon{,' process of 

 dejieneracy. 



SIKKIs'in.K. 



I 



4 





I 



If 



Vertebrae amphiccelous; pteryj;<)idea wanting:; premaxillary and den- 

 tary boiu's toothless: patches on the parasphenoid : two pairs of cera- 

 tobrauchials; a secoiul basibranchial continuous with the first ; several 

 epibrauchials; no otoj^lossal ; the stapes not directly (!onnecti'«l with 

 the (puulrate; mandibular articulation by a baIlandso(^ket joint, the 

 ball on the inaudible, the cotylus in the quadrate. 



In the known j^enera of tlie family the nasal bones are embraced by 

 the spines of the premaxillary bone; the vomeropalato-i)terygoid sirch 



