580 DK. W. G. BIDEWOOD Olf THE HTOBRAITCniAL [May 18, 



of the omohyoideus. The hyoglossus in Pelodytes {hg., fig. 10) is 

 attached to nearly the whole of the ventral surface of the thyrohyal 

 and to the posterior part of the basal plate or body of the hyoid. 

 As already remarked, the greater part of the ventral splint-bone 

 lies buried in the muscle. In the Frog the area of insertion of the 

 hyoglossal muscle (%., fig. 11) is more restricted, and hardly 

 extends on to the basal plate. The posterior end of the geuio- 

 hyoideus internus is, in the Frog, inserted mainly into the ventral 

 fascia of the hyoglossus, only a few straj'^ fibres extending round 

 this muscle to be inserted into the thyrohyal in the position 

 marked ghi. in fig. 11. In Pelodytes the geniohyoideus internus 

 is less bound to the hyoglossus, and its insertion into the thyrohyal 

 {ghi., fig. 10) extends to the posterior extremity of this bone. 



Only two original figures of the hyoid apparatus of Pelodytes 

 have been published. In the first, by Duges (4. pi. 3. fig. 21), the 

 lateral foramina are shown correctly, and their presence is rightly 

 accounted for (4. p. 56) by the union of the hyoid cornua v.ith the 

 antero-lateral processes ; but the dismembered parts of the hyoid 

 arch are wanting. The ventral ossification is represented as of the 

 form of a pair of triradiate bones. The hyoglossal sinus is not 

 sufficiently enclosed in front, nor is the postero-lateral process of 

 the hyoid shown of sufficient length. The second figure, by Parker 

 (12. pi. 23. fig. 3), shows the lateral foramina, but the external 

 enclosing cartilages are represented as in contact, and not con- 

 fluent with one another. The dismembered parts of the hyoidean 

 cornua are introduced into the figure, but they are too rod-like in 

 shape and fail to exhibit the lamellar expansion. The hyoglossal 

 sinus is more enclosed than in Duges's figure, and is consequently 

 more true to nature. The A'entral splint-bone, however, is tri- 

 radiate and unsymmetrical, like one of those figured by Duges. 

 The figure given by Cope (2. pi. 76. fig. 6) is admitted to be based on 

 those of Duges and Parker, and thus calls for no special criticism. 



In the tendency for the processus anteriores to narrow the 

 opening of the hyoglossal sinus, in the presence of lateral foramina, 

 and in the dismemberment of the hyodean cornua, the hyobranchial 

 skeleton of Pelobates very closely resembles that of Pelodytes. 

 My attention was directed towards this genus by Mr. Boulenger, 

 who kindly supplied me with specimens of Pelobates fuscus, and at 

 the same time expressed his conviction that the hyoidean cornua were 

 disjointed in all those genera which he includes in the family 

 Pelobatidae (1. p. 432), and that Parkei-'s figure of the hyobranchial 

 skeleton of Pelobates (12. pi. 25. fig. 9) showing the hyoidean 

 cornua continuous was incorrect. I am happy to be in a position 

 to confirm bis suspicions with regard to Parker's figure, and, as 

 the matter is so important, I trust I may be pardoned for a slight 

 digression here from the genus which forms the subject of this 

 contribution. In the hyobranchial skeleton of Pelobates (fig. 12) 

 the anterior processes are directed inwards and slightly backwards, 

 exactly as in Pelodytes, but they do not reach the median line. 

 The Interal foramina are smaller and more pear-shaped, and in 



