Notes on some Hydromedusae from tlie Bay ot" Naples. 555 



eggs witliout becoming free, tlio I bave not notieed this feature 

 among male colonies. 



It slioiild also he said tbat in tbe species under consideration 

 tbe g'ouopbores in tbeir earlier stages of development sbow everv 

 aspeet, wbetber of form or structure, of sessile sporosaes. But siuce 

 tbese come to matnrity witbin a few days it would seem as if 

 Weismann conld bardly bave failed to distinguisb tbe development 

 of tbe medusa and its probable birtb. Moreover, be deseribes tbe 

 gonopbore as baving a ramified spadix. Wbile tbis may be tbe 

 case during early development, in tbe mature medusa it bas entirely 

 disappeared. Wbetber bere again tbe difference of sex may inveivo 

 differeuce of structure must remain an open question , at least for 

 tbe present. 



Incidentally it may be wortby of remark tbat Weismann's spe- 

 cimens were obtained from considerable deptbs, '40 meters', and 

 from tbe sbell of a species of Murex, whììe as noted above tbe 

 present specimens were ali found on a sbell of anotber genus and 

 at small deptbs. 



Wbile owing to tbe fact tbat only one sex bas been available 

 for tbese comparisons and from wbicb to formulate diagnostic de- 

 tinitions tbere may naturally remain some doubt as to tbe distinct- 

 ness of tbe species, I am, bowever, strongly convinced of its spe- 

 cific independence, and venture to propose for it tbe uame Paclìij- 

 cordyle Weismanni, in bonor of tbe autbor of tlie genus and bis 

 distinguisbed contributions to hydroid morpbology. 



Specific Diagnosis. 



Tropbosome: Colony arising from a delicate, reticulated bydro- 

 rbiza. Hydrocaulus sparingly brancbed, from 3 — 8 mm bigb. Peri- 

 sarc somewbat dense, not extending beyond tbe base of tbe bv- 

 drantb, dull yellowisb brown in color. Hydranths club-sbaped, witb 

 sub-conical bypostome. Tentacles from 8 — 16, filliform, becoming 

 delicate and tbread-like wben fully expanded (PI. 21 Fig. 1). 



Color: Hydrantb body orange or reddish, bypostome wbitisb. 



Habitat: Upon the sbell of Fusus rostratus. 



Gonosome: Medusa buds borne on side of stem, rarely on lateral 

 brancbes, pear-sbaped as tbey approacb maturity, seldom more tban 

 two or tbree on a single polyp, tlie entire gonopbore enclosed witbin 

 a sbeatb of pensare (gonangium?). The medusa escapes from tbe 

 capsule by rupturing or dissolving tbe distai end, after wbicb the 



