14 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.11 



Holotype. — AHF no. 5. 



Type locality. — Isabel Island, Mexico; 40 m; dead shells and sand. 



Distribution. — Same. 



Material examined. — 

 Sta. 974-39 Isabel Island 5- 9-39 Shore 



Remarks. — This sponge is close to Plocamia karykina of California, 

 but the tylostyles are much longer (18 ^a by 340 ii) and there are 

 strongyles instead of tylotes. The most interesting feature of this specimen 

 is the peculiar contortion of the palmate isochelas. One palm on nearly 

 all of them is turned at right angles to the other, making them difficult to 

 identify as to type. This type of contortion is common with sigmas but 

 relatively rare with chelas. Such contortion never occurs in F. karykina 

 from California. 



Genus PLOGAMIONIDA Topsent 



Plocamionida igzo de Laubenfels 



Plate 18, Fig. 36 



Plocamia igzo de Laubenfels, 1932, p. 102. 

 Plocamionida igzo de Laubenfels, 1936, p. 78. 



Diagnosis. — This is an encrusting sponge, stiff to woody in consistency, 

 and drab in alcohol. California specimens are red in life. Oscules are 

 rarely present, and the surface specialization is not evident to the naked 

 eye. 



The endosome is of the plumose type of architecture but not closely 

 organized. 



The spiculation is rather typical of the genus with smooth to micro- 

 spined tylostyles 1 1 ^u, by 190 /x to 35 /.i by 340 /x as dermal spicules, spined 

 tylotes 13 /x by 130/x as principal spicules, and arcuate chelas 14 /x long. 



Holotype.— \].?>.'H.M. 



Type locality. — Point Pines, California. 



Distribution. — Central California to the Gulf of California. 



Material examined. — 

 Sta. 277-34 Isabel Island 3- 5-34 30 m 



Remarks. — Perhaps it is worthy of note that both Plocamionida and 

 Plocamia are found at Isabel Island and are common in the same locality 

 in central California. In view of this fact we might well be justified in 

 considering them, as variations of the same genus. However, the chelas are 

 very different, and this has been frequently used as a basis for separation. 

 The peculiar contorted chelas of the Isabel Island Plocariiia make them 

 resemble, if somewhat superficially, the more primitive types. Dropping 

 the two into synonymy will, probably, be justified but at present awaits 

 further material for study. 



