No. 2. — Maldive Cephalochordates, with the Description of a Neio 

 Species from Florida. By G. H. Parker. 



Introduction. 



Through the kindness of Mr. Alexander Agassiz, to whom my thanks 

 are due, I have had the privilege of studying the cephalochordates col- 

 lected by him in his recent expedition to the Maldive Islands. These 

 consisted of material from three localities. At Timarafuri, Kolumadulu 

 Atoll, a single specimen of the rare Branchiostoma pelagicum Giiather was 

 taken in the net between one hundred and fifty fathoms and the surface ; 

 at Nalandu, Miladummadulu Atoll, a single specimen of a new species of 

 Heteropleuron was dredged in twenty-four fathoms ; and at Hanimadu, 

 Tiladummati Atoll, the dredge brought np from sixteen fathoms tweuty- 

 oue specimens as follows : twelve Heteropleuron maldivense Cooper, two 

 specimens of a new species of Heteropleuron, and seven specimens of 

 a new species closely related to Asymmetron lucayanum Andrews. The 

 exact positions of these localities are well shown in the chart accom- 

 panying Mr. Agassiz's (1903, Plate 1) account of his voyage. 



In addition to this material I have also studied that in the collections 

 of the Museum of Comparative Zoology and of the United States Na- 

 tional Museum. In the former I found seven specimens of a new 

 species of Asymmetron from the coast of Floi-ida. A description of this 

 species is included in the present paper. 



I am indebted to the officers of the National Museum and of the 

 Museum of Cor parative Zoology, especially to my friend Dr. W. McM. 

 Woodworth, for the use of the collections under their charge. 



Description of Species. 



While it is perhaps premature, in view of the rapidly increasing number 

 of species, to discuss at any length the classification of the cephalo- 

 chordates, a survey of the recent literature on the subject shows that 

 the species thus far known fall more or less naturally into three groups, 

 which have at least the taxonomic value of genera. 



The first of these is Costa's original genus Branchiostoma, which, though 

 somewhat restricted by new definitions, has been retained by Kirkaldy 



VOL. XLVI . — NO. 2 



