CHARACTERISTIC DEEP-SEA TYPES. ACALEPHS. 



137 



is still problematical, surrounding the branch where they occur 

 like minute sponges. They are found to consist of a multitude 

 of flask-shaped receptacles. 



The genus Cladocarpus was established by Allman for a re- 

 markable plumularian obtained in the eastern part of the North 

 Atlantic during one of the expeditions of the " Porcupine." 

 Cladocarpus paradisea (Fig. 436), a beautiful species, very 

 striking from its deep and widely separated hydrothecse, was 

 dredged off Tennessee Reef, and off the Samboes, from 174 

 fathoms. 



Hippurella is a genus founded by Allman for hydroids in 

 which the basal ends of the branches carry normal pinnae, while 

 the outer end of the same bear verticillately arranged ribs modi- 

 fied for sheltering the sexual bodies. Hippurella annulata 

 grows in tufts, numerous undivided stems springing from a com- 

 mon base. (Fig. 437.) It is of a rather rigid habit; it was 

 dredged off Pacific Reef, from 283 fathoms. 



In Callicarpa we have whole branches specialized and modified 

 for the protection of the sexual bodies. In Callicarpa grac/fi* 

 (Fig. 438) the gonosome closely resembles a spike of wheat, and 

 springs by a short peduncle immediately from 

 the main stem. (Fig. 439.) 



The most important of the family of Plumu- 

 laridae devoid of movable neniatophores is Pleu- 

 rocarpa, dredged from the neighborhood of the 

 island of St. Vincent in 95 fathoms. In the 

 single known specimen the gonosome (Fig. 440) 

 certainly is the most extraordinary modifica- 

 tion of the branch serving as a protection 

 for the sexual bodies thus far found among- 



O 



plumularians. The basket - shaped structures 

 called corbulae, which serve the same purpose 

 in other genera, are, as Allman has shown, 

 modified pinnae, and not, as in Hippurella, 

 Callicarpa, and Pleurocarpa, a branch or por- 

 tion of a branch bearing pinnae modified to 

 become specialized bodies with the form of cor- 

 bulae. 



Fig. 440. 



Pleurocarpa ramo- 

 sa ; magnified. 

 (Fewkes.) 



