BIGELOW: MEDUSAE AND SIPHONOPHORAE. 377 



which lack them may have lost them through damage in capture or 

 preservation. 



Color. After preservation in formalin, manubrium, large tentacular 

 bulbs, and the pigment-spots, or ocelli, on the rudimentary tentacular 

 bulbs, are yellowish brown. 



Bythotiaridae Maas. 



Calycopsis Fewkes, 1882. 



{Sibogita Maas, 1905). 



The species described below bridges the gap between Calycopsis 

 and Sibogita. According to Vanhoffen (1911, p. 214) these two genera 

 are separated by the fact that in Sibogita the centripetal canals unite 

 with the radials, or with each other, whereas in Calycopsis they are 

 either permanently blind, or join the cruciform base of the manubrium; 

 a view accepted, though with reserve, by Hartlaub (1913), and tacitly, 

 by me in an earlier paper (1913). But it is obvious that this difference 

 is a minor one, centripetal canals joining radials, or manubrium, ac- 

 cording to their location on the subumbrella. And as some of the 

 centripetal canals in one of the specimens described below join the 

 former, some the latter, some of its quadrants would belong to one 

 genus, others to the other, were both to be recognized. 



Eight "species" of Calycopsis, as here defined, have been described 

 from the deep-sea expeditions of recent years: C. typa Fewkes (inch 

 C. nauarchus Bigelow, 1909b); C. geometrica Maas (1905); C. simulans 

 Bigelow (1909a); C. horchgrevinki Browne (1910); C. chuni and C. 

 bigelowi Vanhoffen (1911); C. nematophora Bigelow (1913); C. 

 valdiviae Hartlaub (1913): the relationships, of most of these, I have 

 discussed elsewhere (1913, p. 21). Calycopsis typa, C. simulans, C. 

 chuni, and C. horchgrevinki are closely allied to one another structurally; 

 being separated only by such minor characters as relative number of 

 canals and tentacles ; presence or absence of an apical depression ; and 

 regularity of the sexual folds. And it is possible that the last may be 

 a young stage of one of the others (1913, p. 22). Calycopsis geometrica 

 is, however, sharply marked off from the others by the union of the 

 centripetal canals with the radials, instead of with the manubrium; 

 C .'nematophora by its labial nemotocyst knobs, and by the structure 

 of its gonads; C. valdiviae, founded by Hartlaub for the specimens 

 recorded by Vanhoffen (1911, 1912) as C. typa, by the fact that the 



