1911] Michael: Chaetognatha of the San Diego Region. 35 



In comparing S. Ujra from San Diego with Fowler's (1905) 

 description and figures of S. furcata, one can not fail to see a 

 great resemblance, brought out especially in his plate 4, figures 

 9 and 10. Furthermore the structure of the seizing jaws de- 

 scribed by Krumbach (1903) for S. furcata, tallies except in two 

 points, with the jaws in S. lyra from this region. The two ex- 

 ceptions consist, first in the absence in S. lyra of the cucumber- 

 shaped area near the base of the shaft in which the pulp is absent 

 from the canal, and, second, in the fact that the point, near its 

 base, makes an angle with edge and back of shaft. 



Twice Fowler has been on the point of asserting identity 

 between the two species. In his report on Biscayan Plankton 

 (1905, p. 64) he says of iS'. lyra: '"Krohn very likely had furcata 

 before him/' Later, in the Siboga Report (1906, p. 33) he says: 

 "A few specimens with this label [*S*. lyra Krohn] were received 

 from the Zoological Station in Naples. / still think that this 

 species is probahly furcata SteinJiaus. . . . But on spirit ma- 

 terial it is impossible to feel positive o)i tJiis point."' [Italics 

 mine.] 



Finally, through the excellent work of Ritter-Zahony (1908) 

 there is practically no doubt left as to the identity of these 

 two species. He finds that *S'. furcata is really a younger stage 

 in the development of -8. lyra. 



In comparing »S*. lyra from San Diego with the description 

 of S. u-ltartoni, the similarity of the two species is very striking. 

 Below are given measurements of S. whartoni taken from Fow- 

 ler's (1896) original description and drawings. 



TABLE 5 



Measurements of S. whartoni 



(All measurements made in per cent of total length of animal.) 



Length Anterior fin Posterior fin Number of Number of Number of 



in Length anterior posterior seizing 



Width of tail Length Width Length Widtli teeth teeth jaws 



mm. 



aO-45 6. 6-10. .T 20-26 44-66 2.8 19-33 5.7 3-5 5-7 8-10 



In comparing these measurements with those just given for 

 8. lyra, the only differences consist in the greater length of 

 anterior and posterior fins. San Diego material has yielded no 



