No. 434-] 



NOTES AND LITERATURE. 



M7 



not related to the stickle-backs. Another new order, Mesichthyes, 

 is proposed to include the Haplomi, Synentognathi and Percesoces. 

 But while these groups are closely related, they differ almost as much 

 among themselves as the Haplomi differ from some Isospondyli or 

 the Percesoces from some Percomorphi. It is not clear that the 

 Phthinobranchii really differ much from the Percesoces. especially 

 since Mr. Starks has shown that the interclavicle, or infraclavicle, 

 supposed to distinguish the former, is merely an expansion of the 

 hypocoracoid, and that it is wanting in Macrorhamphosus, Centriscus 

 and Aeoliscus among the Hemibranchs. The arrangement of these 

 transitional fishes in distinct orders, or suborders, offers veiy great 

 difficulties, because the groups, adopted though natural, are not set 

 off by strong characters. 



The Chaetodonts, Labroids and Pomacentrids are placed first 

 among Percomorphous fishes — for no evident reason, as the Berycidae 

 are more primitive in structure and earlier in time. Surely Chaeto- 

 dipterus does not belong to Chsetodontida:, nor Priscacara to the 

 Pomacentridae, nor Platax to the Carangidae. 



Erismatopterus, Amphiplaga, Asinedps and Trichophanes are 

 placed in the Aphredoderidae. Near the Aphredoderidae. would be 

 safer. The suborder Pareioplitae replaces the preoccupied name 

 Loricati for the mailed-cheek fishes. 



Dr. May has earned the lasting thanks of his brother ichthyologists 

 for the pains he has taken in this work, and the portions treating of 

 the groups higher than fishes will doubtless be found as carefully 



' David Starr Jordan. 



Notes. — Ikeda {Journal of the College of Science, Tokyo, Vol. 

 XVII) has made an extended series of experiments to determine the 

 mode of closure of the blastopore and the position of the embryonic 

 body in amphibian eggs. He shows that the results obtained by 

 puncturing eggs and by other similar methods can never be depended 

 upon to reveal the normal course of development, for widely differing 

 results are obtained depending upon the position of the puncture. 

 He believes that the embryonic body in Amphibia may be formed 



parts of the blastoporic lip enclose the yolk-mass, a rate which 

 determines the final closing point of the blastopore and consequently 

 the position of the embryo. 



