SKELETON" OF THE ANUEOUS BATEACHIAITS. 483 



the triangular space at the side of the copula. The width of the 

 copula is only one half that of the pars reunieus, whereas in 

 Itana the two are nearly equal in breadth. The laryns is ex- 

 ceptionally far back, being nearly in a line with the posterior 

 extremity of the fourth ceratobranchial. In no early Anuran 

 tadpole does the larynx actually lie in the laryngeal sinus, for 

 the latter name is anticipatory, and refers to a space which, in 

 the adult, lodges the larynx ; but in Bufo the larynx is farther 

 removed from the sinus than is usual in larvae of this stage. 



HTLIDiE. 



In the proportions of the pars reunions, the copula, and the 

 spaces at the sides of the latter, the larval hyobranchial skeleton 

 of Hyla approaches more closely to that of Rana than does that 

 of Bufo. The first three pairs of spicula are a little longer than 

 those of the frog, but the difierence is slight. The line of de- 

 marcation between the hypobranchial cartilage and the fourth 

 spiculum cannot be made out, the two cartilages being more 

 continuous than in Rana. 



The larval skeleton of Nototrema w as examined by Parker, but 

 not figured. It is described as being quite normal (8. p. 188). 

 The meagre figure of Syla by Stohr (15. Taf. iii. fig. 11) shows 

 only the hypobranchial cartilages and the basal ends of the 

 ceratobrauchials confluent with them. 



Pelobatidjs. 



The three genera examined exhibit considerable uniformity of 

 structure. The space at the side of the copula is large and 

 triangular, the symphysial line between the hypobranchial plates 

 is shorter than the antero-posterior diameter of the copula, and 

 the ceratohyals are large in proportion to the branchial skeleton. 

 The larval hyobranchial skeleton of Relobates has already been 

 figured by Duges (3. Taf. xiii. fig. 75) and Schulze (14. Taf. i. 

 fig. 5), and that of Pelodytes by myself (12. fig. 1). 



The fibrous band which so commonly stretches across the 

 hyoglossal sinus is clearly distinguishable in Pelobates and Lepto- 

 hrachium ; but on examining my former preparations oi Pelodytes, 

 and several new ones as well, I am still unable to detect it in 

 this genus. The copula is considerably longer than broad in 

 Pelohates (fig. 8, cjo.) and LeptohracJiium (fig„ 4), but it is some- 

 what more hexagonal in Pe^o^y^es, The pars reunions in Pelo- 



