Hi INWARD T. BROWNE. 



tentacles on the one half of the umbrellar margin, and on the other half only twelve 

 small bulbs. Another specimen has one short tentacle and five bulbs close together 

 in one quadrant, and the other three quadrants are without tentacles, bulbs, or a 

 circular canal. These specimens are either congenitally abnormal, or else in the process 

 of repairing serious injuries. The latter specimen has every appearance of having lost 

 the greater portion of its original umbrellar margin, and the wound seems to have 

 healed up. The former probably lost one half of its tentacles and has begun to 

 develop a fresh set. 



There is an interesting abnormality in one specimen. From one of the radial 

 canals, not far from the top of the umbrellar cavity, hangs down an extra stomach with 

 a mouth. The stomach has the shape of a slender tube, and bears a few genital folds. 

 The mouth is fairly large for the size of the stomach, and its margin is folded. 



A large Amphipod belonging to the genus Hyperia was found inside the umbrellar 

 cavity of two specimens. 



PERIGONTMUS. sp. ? 



In the ' Discovery ' collection there are four specimens of a little Medusa which 

 looks like a very early stage of a Perigonimus. They are all about the same age and 

 have not been long liberated from their hydroid. The shape and structure of the 

 tentacles are not in favour of this Medusa being a very early stage of Catablema. 



Description. The umbrella is about 1 mm. or less in length and width, with a 

 small conical process on the summit. The stomach is short, and the mouth has four 

 little lips. Four radial canals. The gonads have not begun to develop. There are 

 two long, opposite perradial tentacles, with large tapering basal bulbs. Two very 

 small, opposite perradial and four very small interradial tentacles. 



FAMILY BYTHOTIARID^E (Maas, 1905), Bigelow, 1909. 



Genus SIBOGITA, Maas, 1905. 

 sens. em. 



Generic character. Bythotiaridse with four perradial canals ; with four or more 

 centripetal canals, which may either remain blind canals, or join the radial canals (when 

 the latter have the appearance of being branched), or join the base of the stomach. 



Mr. Bigelow (1909) has recently emended Maas' original definition of the genus, 

 so as to be able to include within the genus a new species called Silogita simulans, 

 found in the Tropical Pacific between Panama and Chatham Island, and also in the 

 Behring Sea ; and another new species called S. nauarchus, found in the Gulf Stream 

 off the North American coast. I now find it necessary to slightly alter Bigelow's 

 definition of the genus for the admittance of a new Antarctic species, named Sibogita 

 borchgrevinki, in honour of the leader of the ' Southern Cross ' Expedition to the South 

 Pole. I think it is advisable to leave the structure of the gonads out of the aeneric 



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