506 



MR. JAMES lUTCHIE ON HYDROIDS 



[May 28, 



and stout proximally, gradually nairow towai'ds the opening, 

 which is furnished with two long, thick -rimmed, latei'al teeth. 

 The operculum is composed of two flaps, in this agreeing with 

 jSiutting's description and diflering from that of Versluys (1899, 

 p. 43), where only a single flap is mentioned. 



Gonoso7ne.— The gonangia, which are characteristic, have not 

 been previously described. They are 1 mm. high, borne on short 

 stalks on the front of the stem, generally one on each internode, 

 and arise from near the base of a hydrotheca. They are strongly 

 compressed from back to front, somewhat flask-shaped, with their 

 greatest diameter (0'6 mm.) near the base and gradually narrowing 

 towards the top, where a slight neck is sui-niounted by a flattened 

 disc bearing two long, incurved, horn-like spines. These are 

 placed, one on each side, immediately above the longitudinal 

 lateral ridge formed by the compression of the gonangium. The 

 gonangia are strongly ridged throughout, the ridges varying in 

 number from five to eight. The gonangial contents escape through 

 a longitudinal slit with toothed edges, stretching along the flattened 

 top of the gonangium from " horn" to " horn." 



Text-fie-. 144. 



hLst 



Male Gonosome of Sertularia versltiysi. 



ap., aperture with toothed lips through which gonangial contents escape ; w., wall 

 of gonangium ; ffub., gubernaculum ; sp., spermarj- ; col., central column of 

 gonophore; ^ow.,'gonophore ; eci., ectoderm ; eiw^., endoderm ; 6Zs#.,blastostyle. 



A peculiar modification was noted in one of the specimens 

 examined, where the distal and posterior poi'tion of a biunch- 

 internode had become free and was prolonged into a straight 



