J04 MEDUS-'E. I. 



therefore, to state their exact number; in well-grown siDecimens there nia\- be about 200-250 warts. 

 The ectoderm of the warts is somewhat thickened (Plate V, fig. 9). On the abaxial side of some of the 

 warts may be found a small tenon, a rudimentary tentacle. 



The marginal vesicles are very numerous, about half as numerous as the warts; they are 

 situated, with a broad base, in the middle of the adaxial side of the warts, close to the velum (Plate V, 

 fig. 9J. ') Marginal vesicles are never found on warts provided with tentacular rudiment. As all of the 

 material at my dispo.sal has been preserved in formalin and left there for several yeans, the concretions 

 of the marginal vesicles have been dissolved; according to Allman (1871) the number of concretions 

 in each marginal vesicle varies from 4 to 20 in one and the same specimen. 



The velum is well-developed and as broad as the length of the tentacular bulbs. 



In living specimens the tentacles are said to be light pink. 



Though this medusa is very common in the North Sea and adjacent waters, no descrip- 

 tion has been given since 1848 (Forbes). It was first discovered by G.Johnston (1833) ^^''^° made a 

 short description and a somewhat rough figure of the species. A very fine drawing was given b\- 

 Dal veil (1847 — 48). The description delivered by Forbes (1848) was rather incomplete. A few mor- 

 phological remarks are found in the works of Allman (1871) and Bohm (1878). The description in 

 Haeckel's monograph (1879) is based on the descriptions and drawings of Dalyell and Forbes. — 

 The records on the occurrence of the species are likewise rather few. It is no wonder, therefore, that 

 Mayer (1910, p. 319) has an entireh- incorrect interpretation of the relationship and distribution of the 

 species. Mayer suggests that Tiina bairdh' ma\' pro\e to be the }onng of Tima forinosa which is 

 found off the Atlantic coasts of New England, and that it is an arctic form occasionally appearing at 

 the coasts of Scotland. 



Tiiiia forniosa L. Agassiz reaches twice the size of Tima bairdii and has about 32 tentacles 

 of three different sizes; according to Bigelow (1913, P- 36) the number of tentacles may amount to 

 39; it has about 100 marginal warts, whereas Tima bairdii, though it is a smaller species, ma\- ha\e 

 more than 200. Mayer (1910, p. 317) and Bigelow (1913, p. 36) confirm the statement of A. Agassiz, 

 that the marginal vesicles in Tima formosa alternate with the warts, being placed in the spaces be- 

 tween the latter; in Tima bairdii they are placed on the warts themselves (see above |. The two species 

 nuu' be nearly related to one another, but the\- are clearlv distinct species. 



More peculiar is the suggestion of ]\Iayer (1910, p. 319), that Tima flavilabris Eschscholtz 

 might be the \oung of Tima formosa. It is not ver\- likeh- that a large species with about 80 short 

 tentacles might be a young stage of a smaller medusa with onh' 32 tentacles. Tima flavilabris Esch- 

 scholtz from the Azores i.s, without an\- doubt, identical with Tima liiciiilaiia Delle Chiaje from the 

 Mediterranean, //rt77/rtZ'/-/V being the correct name of the species^ 



Besides the .species already mentioned, we know another Atlantic species of Tima, viz. Tima 

 teuscheri Haeckel from the coast of Brazil, pos.se.ssing 8 long and 40 short tentacles. 



■I A. .\gas.si/. ill his description of Tima foriiwm states that the inarginal vesicles are situated in the spaces between 

 the warts. 



2) The question of the correct name of this species will be discussed in a later work. 



