REPORT ON THE DEEP-SEA MEDUSAE. 55 



the first Lucernarid from the deep-sea, was not taken during the Challenger expedition, 

 but was part of the spoil of a subsidiary cruise in H.M.S. " Knight Errant," organised by- 

 Sir Wyville Thomson in the summer of 1880, with the view of verifying some of the 

 Challenger results. I am obliged to him for giving me an opportunity of including this 

 species in the list of Challenger Deep-sea Medusae, as in many respects it has a 

 peculiar interest as a link between the preceding Tesserantha and the following 

 Periphylla. 



The umbrella (PL XVI. figs. 1-8) is of a roundish bell shape, or almost pyriform, 

 only a little longer than broad, and adhering by a very short peduncle at the aboral pole. 

 The whole length (or height) (including the peduncle) of the spirit specimen examined 

 came to 60 mm., the greatest breadth (in the middle of the height) to 50 mm. As, 

 however, the specimen was strongly contracted, the height in the living animal would 

 come to at least 70-80 mm., and the breadth to 55-60. This species, as well as the two 

 closely allied species, Lucernaria quadricornis, and L. pyramidalis belong to the largest 

 species of the family Lucernaridse ; the latter has a much shorter stem but a smaller cup. 



The peduncle (" pedunculus," p>), by which the bell-shaped cup fixes itself to the 

 bottom of the sea, is rudimentary and slightly developed in Lucernaria bathyphila, as in 

 all other species of the family. It rather resembles the " apical process or conical process " 

 of the Tesseridae, from which it is probably derived (System der Medusen, 1879, p. 365, 

 taf. xxi., xxii.). Its length amounts, at most, to one-sixth of the whole length of the 

 body, but cannot be sharply defined, as the thicker oral end of the club-shaped peduncle 

 passes gradually, without distinct boundary, into the cup. The thinner aboral end is 

 truncated, and has a small roundish disc on the surface of the point of adhesion (fig. 8). 

 This plate has numerous adhesive cells (" colletocystae ") in its thickened exoderm, it 

 lies in irregular folds, and is divided by four deep interradial furrows into four perradial 

 swollen lobes (fig. 8). Each furrow passes a little way into the exumbrella of the 

 peduncle, so that it also appears four lobed in a transverse section above the disc 

 (fig. 13). The four interradial, longitudinal furrows of the exumbrella of the peduncle 

 have four corresponding gastral taeniola in its inner wall (figs. 1, 2, 21, ft); these are 

 the important longitudinal, gelatinous selvages, already found in Scyphostoma, which 

 traverse the entire length of the peduncle, and pass immediately below into the four 

 interradial septa of the gastral pouches (fig. 12, Jos). In the horizontal section these 

 tseniola appear almost egg-shaped, compressed laterally, and only connected (as by a 

 peduncle) by a very thin gelatinous plate (fig. 14, ft) with the wall of the umbrella 

 peduncle, from which they project centripetally inwards. The gastral hollow space of 

 the peduncle is thus divided into four perradial peduncle grooves (fig. 13, cp) which 

 communicate by narrower clefts with the central basal stomach (gb), and form a regular 

 maltese cross seen in transverse section. The peduncle in our species is, however, one- 

 chambered, as in all species of the genus Lucernaria (in the stricter sense). (System der 



