54 BULLETIN 34, UNITED STATES NATIONAL MUSEUM, 



AMBLYSTOMA OPACUM Graveuhorst. 

 (Plates 19-2L) 



AmMystomn opacn, Baird, Journ. Ac. Phila. (2) i, 1850, p. 2S3 ; Gray, Cat. Balr. Grad. 



Brit. Mils., ed. i, p. 33, I8r)0 ; Hallowell, Journ., Pliila. Acad., iv, 3.')l. 

 Salamnndi-a opaca, Graveuh., Ueber d. Zool. Syst.,p.431, and Delic, p. 7.5, PI. ,10; Dniii. 



& Bibr., p. 06. 

 Salamandra fasciata, Green, Journ. Ac. Phila. i, 1818, p. 350; Holbr. N. A. Hcrp., v, 



p. 71, PL xxrn; Dekay, N. Y., Faiiii , Ri^pfc., p. 77, PL 17, lig. 40. 

 Amblystomafasoiatiini, Dam. & Bibr., p. 103, PL 101, rtg. 5. 

 Amhlijstoma opaciim, Cope, Proc. Ac. Phila. 1867, p. 173; Stranch, Salam., p. 63; Bou- 



lenger. Cat. Batr. Grad. Brit. Mns., ed. ii, 1882, p. 40. 



Body swollen, thick, cylindrical, depressed; skin perfectly smooth, 

 altlion<]^h under a lens everywhere showing minute simple pores or pits 

 connected with the glands, which are seen every wliere on the body and 

 tail, except, perhaps, on the lower part of sides, belly, and beneath the 

 head ; on the tail, however, they are most developed on the upper half. 

 There are no regular patches of more conspicuous pores on the head 

 and parotoids, as seen in A. punctatum. 



Head rather broad, depressed, its greatest width about f the length 

 from snout to gular fold, and about | the distance to insertion of hind 

 legs. Axial length of mouth half that to gular fold, which is inter- 

 rupted ou the nape; a constriction behind the angle of the mouth, with 

 a lateral groove (or ridge) connecting the two as in A. punctatum. Dis-' 

 tance from snout to gular fold not quite 3^ times in that to insertion of 

 hind leg. The eyes are moderate; the pupil circular. The general re- 

 lation much as in A. punctatum. 



Body nearly cylindrical, but decidedly depressed. No indication of 

 a dorsal furrow. Eleven well marked costal furrows including the in- 

 guinal. There are about four pelvic furrows ; those on the base of the 

 tail are distinct anteriorly, but gradually become fainter. 



The tail is oval or subelliptical in cross, section, though without any 

 indication of a keel. It is nearly cylindrical at base, though slightly 

 compressed, becoming more and more so to the pointed tip. It is 

 thicker above than below, and measured from behind the anus is con- 

 tained 1^ times in rest of the length. The lateral groove on the tail is 

 less distinct than in A. punctat%im. 



The digits are linear, depressed, but without any indication of web 

 or margin. The third or longest finger is one-third the distance from 

 its tip to the elbow (contained three times). The lateral ones are quite 

 short. The fourth toe is longest, and contained 2| times in the distance 

 from its tip to tlie knee; the 3, 5, 2, 1 are successively shorter, or the 

 fifth and second are about equal. The distance between the outstretched 

 toes is contained about once and two-sevenths in the length from snout 

 to behind anus. 



The tongue is thick and fleshy, as in A. punctatum, though larger in 

 proportion, and filling the mouth more. The teeth are in one transverse 



