OCR Text |
Show 1903.] MEDUSAE FROM BRITISH COLUMBIA AND ALASKA. 167 pear-shaped tentacle-bulbs, having each two nematocyst -pads ; the relatively short proboscis and tentacles. Fewkes (14) has described a Medusa from the Southern coast of California under the name of Syncoryne rosario, the hydroid form of which he thinks is the Coryne rosario of Agassiz. Although he figures it with no apical process it is undoubtedly a true Codonid. It seems to be very closely related to our species, so far as can be determined. Possibly it is a southern variety, or possibly the two are identical. From Fewkes's description it is difficult to definitely identify his species. While it is possible to determine little from his figures and description (the latter answering for almost any known Codonid), it seems his species possess a rather sharp conical bell, no apical process, and a proboscis a third shorter than in our species. On the other hand, if he identifies it with Syncoryne or Coryne rosario, then from what we know of Agassiz's (2) description of this medusa, the bell would not be so pointed, and the proboscis would be longer than in our species. In a memoir published the same year as the paper mentioned above, but in a different journal (15), Fewkes names it Syncoryne occidentalis, sp. nov.; no reference is made to his former paper or classification, the same drawing and description being used for both papers. It is unfortunate, after finding this Medusa in such abundance at different places on the Californian coast, he has not given us a more definite description. Brown (8) has remarked, in speaking of C. pulchellum, that while he has always found the apical process (the " Scheitel- Aufsatz " of Haeckel) present, the " Stielcanal" is frequently very difficult to distinguish and is sometimes absent. In C. apiculum absence of the " Stielcanal " was never observed, although numbers were examined with this point in view. On the other hand, the apical process, or " Scheitel-Aufsatz," was very poorly marked in some individuals, especially in small and young specimens, some of which had the sharp conical bell shown in Fewkes's figure (14, pi. xxv. fig. 7). Agassiz (2) in his figure of Coryne rosario, p. 177, represents it as possessing a " Stielcanal" but no apical process, the top of the bell being rounded. Haeckel (18) divided the original genus Sarsia of Forbes into the two genera Codonium and Sarsia. Codonium is characterised by the possession of an apical process and " Stielcanal," Sarsia by their absence. While Haeckel places the Sarsia pidchella of Forbes under Codonium (this species, according to Brown, sometimes having the " Stielcanal" absent), he has retained the Coryne rosario of Agassiz under Sarsia, although Agassiz plainly represented it with a "Stielcanal." Both these forms possess certain characters of each genus. Codonium apiculum differs from C. princeps in the shape of the bell, the tentacles, and the tentacle-bulbs. It also differs |