168 MESSRS. L. MURBACH AND C. SHEARER ON [Juiie 16, 



from C. princeps, figiTred by Gronberg (17), in the shape of the 

 bell, the proboscis, and the tentacle-bulbs. It differs from 

 G. 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 medvisa-buds in the young of Amp)hicoclon 

 fritillaria, Margellium octopunctatum, and Lizzia hlondina. 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 G. 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) G. co7iicuni (ISTachtrag, 

 p. 634) can hardly be compared with G. apiculum. It is also 

 different from G. gemmiferum in the size and shape of the bell, 

 the tentacles, and the tentacle-bulbs. The last-riamed species 

 also produces medusa-buds. 



The various species at present included under the family 

 Oodonidae certainly need careful revision ; until more is known of 

 their individual life-histories it is difficult to estimate their syste- 

 matic value. Undoubtedly, as Brown has suggested, many will 

 prove to be immature stages of other species. Whether this 

 will be the case with G. 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 mm. high by 1 mm. bi-oad 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 theii' outer surface a slight elevation 

 containing the ocellus {cf. Mayer, loc. cit.). 



