C AX AD I AX FISHERIES EXI'EDITIOX, lOl-'rlo 421 



3. A SPECIAL STUDY OF THE CAXADIAX CH.ETOGXATHS, THEIR 

 DISTRIBUTION, ETC., IN THE WATERS OF THE EASTERN COAST. 



By A. G. IIuxTSMAX, B.A., M.B., University of Toronto. 

 , . (With 12 Figures.) 



The transparent worm-like animals of this group were A'ery prominent in the 

 catches, sometimes forming more than half of the entire catch. In comparatively few 

 instances were they lacking. The method employed was therefore a suitable one for 

 studying their distribution, and they are as valuable as any group as an index of the 

 character and origin of the "water. They are free-living in all stages and therefore 

 independent of the presence of banks per se. Their distribution will depend upon 

 temperature, salinity, light, oxygen, currents, and food. 



The measurements given are of the total length. In determining the tail per- 

 centage the tail fin was not included in the measurements. The number of jaws at 

 first increases and later may decrease with age. 



KEY TO THE SPECIES. 



Ai. Two pairs of lateral fins. (Sagitta.) 



Bi. Fins (lateral) adjacent or connected. 



Ci. Anterior fin not extending to ventral ganglion. 



S. hjra. Rather soft and stout. Transparent. Fins with anterior end and inner zone 

 free from rays. 8-10-3 jaws. Tail percentage, 21-14. No collarette. Ovary 

 rodlike. Up to 38mm. 

 C2. Anterior fin extending to ganglion. 



S. maxima. Rather soft and stout. Transparent. Fins with anterior end and inner 

 zone free from rays. 10-11-4 jaws. Tail percentage, 32-19. No collarette. 

 Ovary rodlike. Up to 87mm. 

 B2. Fins separated. 



Di. Fins completely traversed by rays. 



El. Anterior fin extending to ventral ganglion. 



S. hipunciata. Stiff and slender. Rather opaque. 8-10-7 jaws. Tail percentage, 28- 

 21. Short collarette. Ovary rodlike. Up to 25mm. 

 E2. Anterior fin not exteeding to ventral ganglion. 



S. elegans. Stiff and moderately slender. 8-13-8 jaws. Tail percentage, 27-10. Short 

 collarette. Ovary rodlike. Up to 52mm. 



D2. Fins not completely traversed by rays (anterior end and inner zone free). 

 Fi. Anterior fin extending to ventral ganglion. 



S. serratodentata. Stiff and slender. Rather opaque. 5-10 jaws, tips turned inwards 

 and inner edges serrate. Tail percentage, 32-20. Short collarette. Up to 

 24mm. 



F2. Anterior fin not extending to ventral ganglion. 

 Gi. Anterior teeth few (3-5), long and diverging. 



S. hexaptera. Stout. Transparent. 7-10-4 jaws. Tail percentage, 26-16. No collar- 

 ette. Ovary rodlike. Up to 70nam. 



G2. Anterior teeth many (5-11), short and overlapping. 



^. ejiflata. Soft and stout. Transparent. 7-10-7 jaws. Tail percentage, 23-14. Short 

 collarette. Ovary sausage-shaped. Up to 30 mm. 



A2. One pair of lateral fins. 



Hi. Lateral fins on tail only. Two rows of teeth on each side. 

 6551-31i 



