CHARACTERISTIC DEEP-SEA TYPES. ACALEPHS. 



135 



by the " Blake." In its affinities, Gleba is one of the most 



problematical of all the siphonophores. Like the physophores, 



it has two rows of nectocalyces, but no 



true float or covering scales. Moreover, 



in the physophores the nectocalyces nearest 



the float are the smallest and the last to 



form, while those at the opposite end are 



larger. In Gleba the bells at the anterior 



extremity are fully formed, while those at 



the posterior end are least developed. 



We have two or three species of a dis- 

 tinct group of siphonophores, known as the 

 Calycophorse, one of the most common of 

 which is Diphyes acuminata. (Fig. 430.) 

 Another species, belonging to the genus 

 Epibulia, was also collected ; it is similar 

 to a Mediterranean species, and is probably 

 the same as that recorded from the coast of 

 Greenland by Leuckart. The genus Aby- 

 la, A. triyona, was found in the Caribbean 

 Sea, and fragments of a large Praya were 

 observed near the Tortugas. I have al- 

 ready alluded to this group of siphono- 

 phores as driven into Narragansett Bay 

 during the summer. 



The first extensive report on deep-sea 

 hydroids was based upon the collections 

 made by Pourtales in the Straits of Florida. 

 They are described by Professor Allman, 

 in one of the most important memoirs ever 

 published on this group. The subsequent 

 explorations of the " Blake " added a num- 

 ber of genera possessing most important 

 morphological characters. As has subse- 

 quently been found in other collections of 

 deep-sea hydroids, a majority of the genera 

 collected belong; to the Plumularidse. A spe- 



r Fig . 430. _ Diphyes acu- 



cies ot the genus Aglaopnenia (A. crenata) minata. f. (Fewkes.) 



