ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 389 



from Naples. The colonies grew on shells of Nassa. The hyclrocaulus 

 springs from a network of creeping hydrorhizal tubes, reaches a height 

 of 4-8 mm., and is either simple or furnished with a few branches, 

 which arise acutely from the stem and are seldom subdivided. A well- 

 developed perisarc is present, slightly and irregularly wrinkled through- 

 out its length. It is covered with a dense coat of foreign particles, and 

 vvidens at the base of each polyp into a shallow cup-like expansion. Up 

 to four to eight polyps are borne on a single liydrocaulus, and these are 

 furnished, according to age, with six to sixteen tentacles in a single 

 whorl. 



Blastostyles arise on the stolon and on the hydrocaulus : their basal 

 portion is covered with perisnrc which terminates in a cup-like expansion 

 similar to that beneath the polyps. Around the blastostyle the 

 sporosacs, in general eighteen to twenty-four, and exceptionally as many 

 as thirty-four to forty, are grouped in a spherical or elongate cluster. 

 The sporosacs arise from a zone encircling the middle region of the 

 lilastostyle, the tip and base of which project beyond the mature 

 cluster. In the adult state the sporosacs are free-swimming, are 

 furnished with one tentacle, and are covered with cilia. Female 

 sporosacs bear a solitary oocyte. The structure of the sporosacs is of 

 the simplest nature, as they consist of a single layer of ectoderm 

 between which and the endodermal spadix lies the oocyte or a mass of 

 spermatozoa. 



The authors discuss the medusoid- and polyp-homology of the 

 sporosacs of Vkoryne. There is no evidence that they have undergone 

 retrogression from the condition of medusoids or medusoid gonophores. 

 It is also unsatisfactory to regard the sporosac as a modified hydranth. 

 Indeed both comparisons are forced. The sporosac of Dicoryne is 

 essentially an outgrowth of almost the simplest possible form, pro- 

 duced apparently by the stimulus due to the presence of the germ- 

 cells. The ectoderm in which these lie grows pari passii with them 

 and forms the envelope for them, the subjacent endoderm — which 

 soon grows out as a " spadix "—is applied to the germ-cells and carries 

 the supply of nutrient material necessary for their growth. This 

 bud-like outgrowth, like other simple buds in the Hydrozoa, produces 

 one or two tentacles, similar in structure to those of a polyp, and 

 eventually becomes free. The most striking difference between such a 

 bud and any other known in the Hydrozoa is its ciliation, which is 

 probably a secondary adaptation. The free-swimming sporosacs of 

 Dicoryne are the only ciliated reproductive members known in the 

 Hydrozoa. 



The fertilized eggs form l^lastulte ; the cleavage is total and unequal, 

 or approximately so. Each blastomere shows a peripheral zone of 

 granules different from yolk-spherules. The endoderm seems to be 

 formed by multipolar immigration, and fills up the segmentation cavity. 

 By the breaking down of the endoderm a coelenteron is formed. 



Campanulina ceylonensis (Browne).* — R. E. Lloyd and Nelson 

 Annandale describe this interesting Hydrozoon, whose medusoid was 



* Records Indian Museum, xii. (1916) pp. 49-57 (3 pis. and 1 fig.). 



