HOMOEONEMA. 141 



Color. — All the present specimens are colorless. This is in contrast to 

 Vanhoffen's observations, inasmuch as he describes and figures the entire 

 entodermic system as red, and states that only such specimens as have lost 

 the entire gastro-vascular structures are colorless. Maas (: 05) likewise 

 represents them as of a pale reddish tint. This difference, however, is not, 

 to my mind, of specific significance, but is probably such a local color varia- 

 tion such as occurs in Nausithoe punctata. 



The present captures show that Halicreas papillosum is very widely 

 distributed throughout the tropical and subtropical waters of all oceans. It is 

 recorded from the Eastern Tropical Atlantic ("Valdivia"), and probably from 

 the western Atlantic, (Gulf Stream H. minima, Fewkes), from the Indian 

 Ocean ("Valdivia"), the Malay Archipelago (" Siboga"), and is of very 

 general occurrence throughout the Eastern Tropical Pacific. Browne (: 08) 

 has likewise recorded a variety, H. antarclicum, from the Antarctic. It is 

 certainly an intermediate form, although a single very fragmentary disc 

 was taken on the surface. 



Homoeonema Maas, 1897 (non Vanhoffen). 

 Haliscera Vanhoffen, 1902. 



Halicreasidae without exumbral papillae ; gonads either proximal or 

 occupying the central one third of the radial canals. 



Following this definition two species, H. glabrum and //. rotundatum, in- 

 cluded by Vanhoffen in Haliscera because of the large number of tentacles, 

 fall into Homoeonema. 



Maas (: 06 b , p. 9) maintains that a new genus should be established 

 for these two, distinguished from Homoeonema by the position of the 

 gonads and by the large number of tentacles ; but considering how slight 

 is our knowledge of the two species, this separation seems to me of 

 doubtful value. 



Specific distinctions between the members of Homoeonema are difficult 

 to draw, because most of the species are so far known only from Van- 

 hoffen's brief descriptions and figures. He lays stress on the form of 

 the gonads as a distinguishing character between //. glabrum, II. rotundatum, 

 and H. conica, but in his figures (: 02 b , taf. 9) these structures are very similar 

 in the three species. The position of the gonads, whether proximal or 

 occupying the central one third of the canals, may well be of specific, 

 even if it is not of generic, importance, and likewise the number of 



