370 bulletin: museum of comparative zoology. 



opening is entirely closed over by the gelatinous substance of the 

 exumbrella, just as Maas (1905, pi. 1, fig. 8) has figured, and Browne 

 (1916) described it, for contracted B. fulva. And this violent con- 

 traction likewise results in 4 longitudinal radial furrows in the exum- 

 brella, not present in life (Mayer, 1910). In the few medium sized 

 specimens which are not contracted, the outline of the bell is much as 

 ]\Iayer has figured it. 



Pandeidae Haeckel. 

 (Sens. em. Bigelow, 1909a; Tiaridae Haeckel, 1879; Hartlaub, 1913 (partim)). 



I have already maintained (1913, p. 12) that the name Tiaridae 

 must be abandoned since Tiara, the generic name, is preoccupied 

 for a mollusc. And though Hartlaub (1913, p. 240) thinks such a 

 change unnecessary, it is in accord with the International code of 

 zoological nomenclature, Art. 15. Hartlaub has recently (1913) 

 given a thorough revision of the famil}-. But while I am in full accord 

 with most of his conclusions, it seems to me wiser to retain the Bytho- 

 tiaridae as a separate family rather than to include them as a " gruppe " 

 (calycopsiden) of the Pandeidae, because the structure of tentacle 

 base and margin, in the various calycopsids, is very different from that 

 of the typical pandeids ("gruppe neoturriden" of Hartlaub). 



Stomotoca L. Agassiz, 1862. 



(Setisu Bigelow, 1909a; Hartlaub, 1913; Vanhoffen, 1913a). 



Pandeidae with 2 large, opposed, perradial tentacles and many 

 rudimentary tentacles; with the manubrium situated on a gelatinous 

 peduncle. 



Mayer (1910) enlarges this genus to include all pandeids with 2 large 

 and many rudimentary tentacles, whether or not a peduncle is present. 

 But this organ is so commonly of generic importance among Medusae, 

 that there seems no reason to deny it that value here. 



The three described species, included in this genus as limited here, 

 »S'. atra A. Agassiz, S. pterophyUa Haeckel, and »S'. divisa Maas, are so 

 closely allied that I have already suggested the unity of the last two, 

 (1909a), while Vanhoffen (1913a) unequivocally unites them all under 

 the oldest name, S. atra; though Mayer (1910) retains all three. No 

 previous student, however, has actually compared specimens from the 



