ON THE CHONDBOCEANIUM OF THE LARVAL HERRING. 1213 



53. On the Morphology of the (yhondrocranium o£ the Larval 

 Herring- [Clupea harengus). By F. H. Wells*. 



[Received October 18, 1922 : Read November 21, 1922.] 



(Text-figures 1-11.) 



Contents. 



Page 



1. Introdnction 1213 



2. Method 1214 



3. External Characters 1215 



4. Discussion , 1215 



5. The Chondrocranium 1217 



a. The 5 mm. Stage 1217 



b. The 10 mm. Stage 1218 



c. The 20 mm. Stage 1221 



d. The 80 mm. Stage 1223 



e The 40 mm. Stage 1224 



/. The 50 mm. Stage 1225 



6. Summary 1226 



7. List of Abbreviations 1228 



8. Bibliography 1228 



1. Introduction. 



This research was started at the suggestion of Prof. MacBride, 

 the work being carried out in his laboratory in the Imperial 

 College of Science, our attention being drawn to the necessity of 

 studying the development of the chondrocranium, in particulai', 

 of the more ' primitive Teleostei hj work being done by 

 Mr. Norman on the Eel, which, like the Herring, has no upper 

 jaw in the early larval stages. 



The paper refers to the larvse of the Clupeoid, Clupea Tiarengxis : 

 all observations and reconstructions were made from these only, 

 although the internal morphology of the Sprat and Pilchard was 

 found to be indistinguisliably similar. The paper describes only 

 the chondrocranium. For convenience, the larvse have been 

 divided into stages as follows : — 5 mm., 10 mm., 20 mm., 30 mm., 

 and metamorphosing stages (40 mm. and 50 mm.). 



Previous work on the skulls of Teleostomi includes the fol- 

 lowing :— Salmon (Parker, 1872; Stohr, 1882; Gaupp, 1903; 

 Boker, 1913), Trout (Winslow, 1897), Qasterosteus (Swinnerton, 

 1920), Gydopterus (Uhlmann, 1921), Syngnathihs (McMurrich, 

 1884), Amiurus (Kindred. 1919), Selachian (Parker, 1879); 

 Sewertzoff, 1899), Chondrostei (Parker, 1883 ; Sewertzoff, 1902), 

 Lepidosteus (Parker, 1883 ; Veit, 1911), and a recent paper on 

 Amia (Pehrson, 1922), in which is pointed ont the need for the 

 study of the morphogenetic development of the cranium of the 



* Communicated by Prof. E. W. MacBeide, P.R.S. 



