502 APPENDIX. 



Fam. Hydride. 

 Stokes' Sea Serpent. Hydrus Stokesii. 



Plate 3. 



Grey ; white beneath ; scales of the back, broad, ovate, cordate, 

 keeled ; of the sides larger, and of the belly largest, all keeled ; of 

 the two central series of the belly rather larger, more acute and 

 smooth. Labial shields, 5, 1, 5, high band-hke ; the 4 and 5 

 the highest. 1, cheek scale; 1, anterior, and .3, posterior ocu- 

 lar, the lower liinder largest ; the hinder labial shields behind 

 the eye small, the hinder one smallest. 



Inhab. Austrahan Seas. 



This species is the giant of the genus, being very many times 

 larger than the Hydrns Major of Shaw, {Pelamis Shaivi, 

 Messem.) from the coast of India. The body is as thick as a 

 man's thigh, and it must have been a most powerful and dan- 

 gerous enemy to any person in the water. 



GoNiONOTUS, Gray. 



Head ovate, depressed, covered with small rather acute scales, 

 with 2 small frontal plates just over the rostral in front ; rostral 

 small, triangular, concave in the centre. Nostrils large, rather 

 anterior, in the middle of a rather large plate, N\ith a slight sht 

 to the hinder edge ; labial scales rather larger ; the lower ones 

 with a concavity in the middle of each scale. Eyes convex, 

 rather large, pupil oblong ; throat with small acute scales. 

 Body elongate, compressed, subpentangular ; back covered with 

 very small semicircular scales, with a row of larger ovate keeled 

 scales on each side, and 2 or 3 rows of similar larger keeled scales 

 over the vertebral line ; the sides covered with moderate ovate 

 keeled scales, rather larger beneath the belly, covered with a series 

 of transverse rounded plates. Tail elongate, rather compressed, 

 subpentangular, tapering, like the back above, and with a single 

 series of rounded transverse plates beneath. 



