AEQUORIDAE. 173 



wings extending in either direction along the bell margin. This form was 

 first recorded from the Pacific as Polycanna purpurostoma Agassiz and Mayer 

 ('99, p. 169) ; more recently, however, Browne (: 04) and Maas (: 05) have 

 identified specimens answering the same description with the Mesonema 

 pensile of Modeer. I have myself examined the type of P. purpurostoma, 

 and find that the basal bulbs, not especially described by Agassiz and 

 Mayer, are reducible to the type figured by Browne (: 04, pi. 57, figs. 

 6-8) and by Maas. Identical also with it, as Maas has shown, is Rhegmatodes 

 lac/eus Agassiz and Mayer (: 02, p. 147). For this species the name 3L 

 pensile may be retained. 



2. Mesonema maerodacl ijlum Brandt has since been recorded by Goette 

 ('86), Chun ('96), Agassiz and Mayer (: 02), and Maas (: 05), and is represented 

 by several specimens in the present collection. In this species each tentacu- 

 lar bulb bears a triangular spur-like process clasping the exumbrella ; there 

 are about one half as many tentacles as canals. The species described by 

 Browne as Aequorea maldivensis has, as noted by Maas, the same form of 

 tentacular bulb and about the same proportional number of tentacles and 

 canals. The two are separable only by the form of the mouth, which is 

 described as slightly wider in A. maldivensis than in M. macrodactylum ; but 

 since both Maas's and Browne's accounts were taken from preserved speci- 

 mens, and since in the present series of M. macrodactylum various breadths 

 of the lower gastric wall are represented, I have no hesitation in uniting 

 the two under the older name 31. macrodactylum. 



3. A. globosa Eschscholtz is recorded by Maas (: 05). It is possible that one 

 of Browne's specimens of A. maldivensis with fifty tentacles and only fifty-four 

 canals, in reality belongs to A. globosa. In this species the number of tentacles 

 about equals that of the canals ; the basal bulbs are conical ; the stomach broad. 



4. Rhegmatodes floridanus L. Agassiz. I have examined a series of this 

 species from Australia, from the Fiji Islands (Agassiz and Mayer, '99), 

 as well as from the West Indies, and am unable to find any constant differ- 

 ences between the Atlantic and Pacific specimens. The total diameter of 

 the stomach is very small ; the number of canals is small, not as yet known 

 to surpass twenty-eight ; the disc is thin and soft. This species is closely 

 allied to Rhegmatodes tenuis A. Agassiz, common along the east coast of 

 North America; but the differences in number of radial parts which separate 

 the two have been found to be constant in very large series by various 

 observers. 



