TELEOSTEAN CARTILAGINOUS PECTORAL GIRDLE. 509 



Summary : — In the young of Clupea sprattus, C. harengits, and C. pilchardus 

 about 20 to 30 mm. in length, the right and left coracoid regions fuse' to a 

 solid cartilaginous ventral bar, which becomes bent and again subdivided in 

 later stages. This fusion is probably a specialisation to strengthen the 

 support of the pectoral fins before the complete development of the dermal 

 bones of the pectoral girdle. 



Referexce-letters for Figures 1-6. 



at, atrium ; ha, bulbus arteriosus ; br, branchial arch ; c, coracoid region ; cf, coracoid 

 foramen: cl, cleithrum; hm, hypoglossal muscles; ce,, oesophagus; p, pericardium ; 

 pf, postcoracoid foramen ; pfm, pectoral fin muscles ; pfn, pectoral fin skeleton ; 

 pr, posterior process ; r, radial ; /•(/, distal radial cartilage ; s, scapular process; 

 sf, scapular foramen ; ve, ventricle ; vm, ventral body- wall muscle. 



References' 



1. Dekjugin, K. — -Die Entw. der Brustflosse und des Schultergiirtels bei 



E.voccetus volitans. Zeit. f. Wiss. Zool. xci., 1908. 



2. Gegenbaur, 0.— Unters. zur vergl. Anat. der Wirbeltiere, ii., 1865. 



3. Goodrich, E. S. — Vertebrata Craniatn : Part 9 of a 'Treatise on 



Zoology,' 1909. 



4. Haller, B. — Ueber den Schultergurtel der Teleosteer. Arch. f. Mikr. 



Anat. lxvii., 1905. 



5. Parker, W. K. — A Monograph of the Shoulder-girdle and Sternum. 



Kay Soc, 1868. 



6. Stannius, H.— Handb. d. Anat. d. Wirbelthiere, 2te Aufl., 1854-6. 



7. Swinnerton. H. H. — A Contribution to the Morphology and Development 



of the Pectoral Skeleton of Teleosteans. Quart. Jour-n. Micros. Sci. 

 xlix., 1906. 



8. Swirski, G. — Unters. u. d. Entw. des Schultergiirtels des Hechts. 



Inaug.-Diss., Dorpat, 1880. 



9. Vogel, R. — Entw. des Schultergiirtels der Forelle. Jen. Zeitschr. f. 



Naturw., xlv., 1909. 

 10. Wiedersheim, R. — Das Glieduiassenskelett der Wirbeltiere. 1892. 



