FREE-SWIMMING SPOROSACS OF THE HYDROID GENUS DICORYNE. 273 



A B 



Text-fig. 1. — Diagrammatic sections of A, phanerocodonic, and B, adelocodonicgonopkores. a, ectotheca; b, mesotheca 

 or umbrella ; c, endotheca or ectodermal layer of manubrium ; d, spadix ; e, ova ; /, radial canals ; g, circular 

 canal seen in transverse section ; h, marginal tentacle ; i, ocellus ; k, velum ; I, peduncle of gonophore ; m, general 

 cavity of coenosarc ; n, mouth of medusa. The endoderm is distinguished from the ectoderm by its darker tint. 



[From Allman, 1871, rig. 13, p. 39. 



Printed from the original wood-block, kindly lent by the Council 

 of the Kay Society.] 



Coel. 



CoEL. 



A 



B 



Text-fig. 2. — Diagrammatic sections of female sporosacs of Dicoryne conybearei. A, r a mature sporosac on the 

 point of liberation ; B, a younger stage which shows more clearly the essential simplicity of the sporosac. 

 OffiL., ccelenteron (general cavity of coenosarc) ; Ect., ectoderm; End., endoderm ; 0., oocyte; S.N., neck 

 of sporosac ; S.S., stalk of sporosac ; T., tentacle. The ectoderm is indicated by a pale tint, the endoderm is 

 darker, and the cavity of the spadix and coenosarc is black. 



TRANS. ROY SOC. EDIN., VOL. LI, PART 1 (NO. 6). 



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