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Show 168 MESSRS. L. MURBACH AND C. SIIEARER ON [June 16, from C-. princeps, figured by Grcinberg (17), in the shape of the bell, the proboscis, and the tentacle-bulbs. It differs from C. codonophorum in the shape of the bell and of the peduncle, this species producing medusa-buds. It differs from C. pul-chellum in the shape and size of the bell and the tentacles : this species again produces medusa-buds. Brown (8, p. 473) states that he has found medusa-buds in the young of Amphicodon Jritillaria, Margellium octopunctatum, and Lizzia blondina. He thinks that it is probably characteristic of the immature condition to produce medusa-buds, while in the adult condition there are gonads on the stomach. For this reason he considers it probable that C. gemmiferum and Sarsia proliiera, which both produce medusa-buds, and are regarded as distinct species, will ultimately prove to be only the early stages of other known species. The peculiar shape of the bell in Haeckel's (18) C. conicum (Nachtrag, p. 634) can hardly be compared with C. apiculum. It is also different from C. gemmiferum in the size and shape of the bell, the tentacles, and the tentacle-bulbs. The last-named species also produces medusa-buds. The various species at present included under the family Codonidse certainly need careful revision; until more is known of their individual life-histories it is difficult to estimate their systematic value. Undoubtedly, as Brown has suggested, many will prove to be immature stages of other species. Whether this will be the case with C. apiculum can only be said when its life-history is known. Without any knowledge of this it is difficult to find a place for it under any of the species already known SYNDICTYON A. Agassiz (Haeckel, 18, p. 20). 1. SYNDICTYON ANGULATUM (Mayer). Specific description.-In outline the shape of the bell is that of a truncated oval, 1*5 m m . high by 1 m m . broad at the velum. In the preserved condition it has the peculiar quadrangular form mentioned by Mayer (27, p. 5) in his recently described species S. angulatum. The wall of the bell is thin and is usually covered with nematocysts, but these are absent in some examples. In all but one of the specimens there is a depression in the top of the bell, and this is met by a canal from the subumbrellar surface forming a complete tube through the apex of the bell. This is the remains of the canal originally connecting the animal with its hydroid form. The velum is well developed. The four tentacles are much contracted, apparently swelling at their distal ends, and covered with rows of nematocysts arranged in a spiral manner. The tentacles are attached to the bell-margin by means of large tentacle-bulbs, which bear on their outer surface a slight elevation containing the ocellus {cf. Mayer, loc. cit.). |
