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Show 186 MESSRS. L. MURBACU AND C. SHEARER ON [Julie 16, The stomach is much distorted with food, but is of the usual quadrangular shape, with oral lobes finely crenulated. The four radial canals pass from the circular tube upwards to the gelatinous peduncle, under which they pass downwards to the stomach ; their crossing lies deeper on this account than the point where they enter the stomach (PI. X X I . fig. 3). They are simple. The gonads have the frill-like arrangement on the course of the radial canals, from side to side, similar to their arrangement in other species of this genus, but they are denser and run closer to the circular canal. Colour.-This is hard to determine from preserved material, but it is doubtless somewhat similar to the bright colours in other species of this group. Habitat.-Unalaska, Aleutian Is., collected by Kincaid. Discussion.-Prof. Kincaid states that this species was collected in a small salt lake in the Aleutian Islands, which was doubtless connected directly with the sea by some underground passage, as its surface rose and fell with the tide. These Medusa? were found clinging to stones by means of their attachment-pads, and when disturbed moved a short distance, then re-attached themselves again. This species probably possesses the same swimming-movements so characteristic of the other species of this genus. As already stated, the genus Gonionemus was founded by A. Agassiz for G. vertens, which he procured in the Gulf of Georgia, July 1859. The peculiar angle formed by the tentacles being bent at the adhesive pad or sucker was sufficiently striking to suggest the name Gonionemus for the genus. Haeckel (18) subsequently, understanding this name to mean " kneed threads," changed this to Gonynema*, under which name it appears in his ' System der Medusen.' The resemblance of Gonionemus to Melicertum led A. Agassiz to place it with the latter genus in the family Melicertida?, the elder Agassiz (1, p. 348) placing it under the suborder Sertularia?. Haeckel (18) arranges four of Agassiz's genera among the Trachomedusse, but placed Gonionemus in the family Cannotida?, subfamily Polyorchince, believing, from Agassiz's description or drawing, that it possessed lateral diverticula on the radial canals as already mentioned. N o further notice was taken of this Medusa until one of the present writers, Murbach (32) published a short preliminary report of the occurrence of the genus in the Atlantic at Woods * As Agassiz derived the name Gonionemus from ytovi'a and vijfia, Haeckel's assumption that the first part of the name is derived from yovv is wrong, only the last part of his name is right. Yerkes, in a recent paper (Am. Journ. of Phys. vol. vii. p. 181), has changed the name to Gonionema, in this being followed by Perkins (Johns Hopkins Univ. Cir., June 1902). Since they correctly derive the first part of the name from ywvia, why does this become Gonionema and not Gonianenm in the full name? In preference to further change we have retained the original name. |