THE SIPHON OPHOliAE. 



INTRODUCTION. 



The collection of Siphonophores obtained by the "Albatross" in the 

 Eastern Tropical Pacific in 1904-1905, together with the few specimens pre- 

 viously collected by her in other parts of the Pacific, is one of the most exten- 

 sive series which has been made. Out of a total of forty-six genera and about 

 ninetj^ species which deserve recognition, it contains no less than thirty-five 

 genera and fifty-two species. 



Since formalin has come into use, the preservation of the Siphonophores 

 is no longer attended with any great difficulty, and the collection, as a whole, 

 is in excellent condition. I have already (:09a, p. 11) called attention to the 

 value of chloretone as a stupefying reagent and given short directions for using it. 



Throughout the Cruise I had the opportunity of studying the Siphonophores 

 in life; and of making numerous drawings and these have been of great 

 assistance. 



Two new genera and six new species are described. That no more no\-cl- 

 ties were obtained is, of course, a corollary of the holoplanktonic habit of the 

 group. Especially noteworthy, from the standpoint of morphologj' and classi- 

 fication are: — the discovery of a new Nectopyramis with its Eudoxid, a genus 

 previously known from one specimen; the capture of a large series of Amphi- 

 caryon, previously unfigured and known from one record only; the rediscovery 

 of the Diphyes dubia of Quoy and Gaimard, known only from the original 

 record, and for which a new genus is required, and the discovery of a new species 

 of the same genus; the discovery of a new Rhodalid, represented by a large 

 and excellently preserved series allowing anatomic study; the capture of a 

 large series of the little-known genus Porpema, and of Porpita pacifica. On 

 these two I was able to make a study of the "central organ," as well as of 

 the anatomy in general. 



