460 DR. W. G. RIDEWOOD ON THE 



EXPLANATION OF PLATE 31. 



Fig. 1. Hymcnochirus Boettgeri, male. Hyobranchial, laryngeal, and man- 

 dibulai" skeleton, ventral vievt^. ( X 6.) 



2. Laryngeal skeleton of same, doi-sal view. 



3. Hymenochirus Boettgeri, female. Laryngeal skeleton, and hinder part 



of hyobranchial skeleton, ventral view. ( X 6.) 



4. Laryngeal skeleton of same, dorsal view. 



6. Carpal skeleton of same, dorsal view. ( X 12 ; see page 462.) 



Reference Letiet's. 



So far as has been possible, the lettering used in Plates 8 and 9, Linn. Soe- 

 Journ., Zool., xxvi. 1897, has been adopted in the present instance. 



a. Ala, or great wing of the hyobranchial skeleton. 

 ar. Arytenoid. 

 a^. Angulosplenial bone. 

 hi. Dorsal extremity of vertical cricoid rod. 

 br. Bronchial cartilage. 



c. Dorsal or roofing portion of the cricoid cartilage. 

 c'. Antero-ventral portion of cricoid. 



e". Postero- ventral poi'tion of cricoid. 

 ca. Ossified copula (c/. 6. pi. 2. figs. 1 & 2, oa). 

 ck. Ceratohyal or hyoideau cornu. 

 ch'. Median cartilage formed by the secondary union of the hyoidean cornua 



d. Dentary bone. 



ep. Posterior epiphysis of the thyrohyal. 

 ge. Area of insertion of the m. geniohyoideus externus. 

 gl. Position of the glottis. 

 //.. Hyoglossal foramen. 

 i. Isthmus between the anterior and posterior portions of the branchial 



skeleton. 

 i'. Ligament equivalent to the cartilaginous isthmus of the female. 

 pa. Anterior plate of the hyoidean skeleton (cf. 5. pi. 35. fig. 11, pa). 

 pm. Outline of anterior pai-t of lung. 

 t. Thyrohyal bone. 

 t'. Lamella of cartilage projecting from the thyrohyal bone in the male. 



Note on the Carpus of the new Aglossal Toad, HymenocJiirus 

 Boettqeri. By W. &. Eidewood, D.Sc, i'.L.S. 



(Plate 31. fig. 5.) 



Whereas the carpus o£ Xenopus is comparatively normal, and 

 does not differ in any very essential respect from that of Disco- 

 glossus or Boinbuiafor, the carpus of PijJa is remarkable from 



