REPORT ON THE CHAETOGNATHA COLLECTED BY THE 

 UNITED STATES FISHERIES STEAMER "ALBATROSS" 

 DURING THE PHILIPPINE EXPEDITION, 1907-1910. 



By Ellis L. Michael, 



Of the Scripps Institution for Biological Research, La Jolla, California. 



INTRODUCTION. 



This paper is based upon the chaetognatha collected by the United 

 States Bureau of Fisheries steamer Albatross during the Philippine 

 expedition of 1907-1910. Chaetognatha were taken at 46 stations 

 scattered between the parallels of 21° 31' north and 5° 36' south 

 latitude, and between the meridians of 117° 53' east and 127° 44' 

 east longitude. The collection is represented by 12 species of Sagitta, 

 of which one, Sagitta philippini, is apparently new; one of Pterosagitta; 

 two of Eukrohnia; and one of Rrolmitta. The species of Sagitta, in 

 order of the number of specimens obtained, are: S. enjlata, (2,800); 

 S. Jiexaptera, (700); S. ferox, (600); S. pulchra, (550); S. neglecta, 

 (425); S. bedoti, (350); S. decipiens, (160); S. serratodentata, (100); 

 S. planktonis, (85) ; S. minima, (2) ; and one each of S. macrocephala 

 and S. pTiilippini. Pterosagitta is represented by 32 specimens of 

 P. draco; Eukrohnia by 6 specimens of E. hamata and 5 of E. rich- 

 ardi; and Rrohnitta by 3 specimens of R. subtilis. 



Most of the material was preserved in formalin and is in excellent 

 condition. In some cases, however, alcohol was used. Specimens 

 preserved with it are distorted and the tannin extracted from the 

 corks of the containers has turned most of them quite black, ren- 

 dering identification uncertain and, in some cases, impossible. But, 

 in so far as the collection permits, tables of diagnostic measurements 

 are given for each species, enough measurements being made on each 

 individual to enable reconstruction of its outline. Otherwise, the 

 species are not further described except for those concerning which 

 need of description is indicated by the literature. In lieu of descrip- 

 tions, however, references are given to those published in other 

 reports, particularly to Ritter-Zahony's (1911) revision of the group, 

 which, with two or three exceptions, is adopted as my basis of 

 classification. 



In order to make the report as serviceable as possible, keys are 

 supplied for identifying not only those species obtained during the 

 Philippine expedition but all the species in the group. Several new 

 species and five new genera have been described since my last (1911) 

 report. In addition, Ritter-Zahony (1911) has called attention to 

 and admirably illustrated specificities in the presence and absence 



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