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Branchiostomid.e. 



Genus I. Branchiostoma. 



Sub-genus I. Ampkioxus. 



A. lanceolatus. 



A. belcher i. 



A. californiense. 



A. caribbccus. 

 Sub-genus II. Heteropleuron. 



H. cultellum. 



H. bassanum. 



H. cingalense. 

 Genus II. Asymmetron. 



A. lucayanum. 



Incertje Sedis. B. elongatum. 



B. pelagicum. 



She examined the species as to the state of their gonads 

 and metapleura, and agreed with Willey in retaining 

 such forms as H. cultellum and H. bassanum (both of 

 which have nniserial gonads and asymmetrical meta- 

 pleura, important, and according to Andrews, diagnostic 

 characters of the genns Asymmetron) in the genus 

 Branchiostoma, creating a new sub-genus Heteropleuron 

 for their reception as Willey had suggested. The two 

 forms B. elongatum and B. pelagicum she did not examine, 

 and regarded their position as doubtful, till further 

 specimens were examined. She also described a new 

 species from Ceylon, H. cingalense, with a myotome 

 formula of 39, 16, 8. 



In the same year Gill 1 published a classification of the 

 Cephalochorda, arrived at quite independently of that 

 referred to above. He offered no comment on Kirkaldy's 

 paper which reached him just as his was going to press. 

 His classification was as follows: — 



1 American Naturalist. Vol. xxix. 1895. 



