REPORT ON THE HYDROIDA. 45 



distal portion of the plij'lactocarp was curved over the gonanginm and its snpportino- 

 internode, while its lateral spines were all directed backwards away from the concavity of 

 the curve. 



The morphological significance of the phylactocarp is here sufficiently obvious. There 

 can be no hesitation in recognising in it a modified hydrocladium, in which all the hydro- 

 thecse, except that Iwrne l)y the proximal internode, have been suppressed. It is also 

 evident that the pair of lateral spines carried by every other internode represents the 

 lateral nematophores of the suppressed hydrotheca. Except on the proximal or hydro- 

 theca-bearing internode, and on that on which a gonangium is developed, no representative 

 of the mesial nematophore is to be found. On the gonangium-bearing internode, how- 

 ever, a mesial spine is carried by the front of tlie internode, at a short distance behind the 

 gonangium, and this plainly represents the mesial nematophore of the suppressed hydro- 

 theca. The gonangium liere takes precisely the place which would have been occupied 

 by a hydrotheca had this been developed. 



It may be a question whether the phylactocarps described aliove, which when 

 examined were found destitute of gonangia, are provided with gonangia at other times, or 

 whether they arc really sterile ramuli, with some other physiological significance ; at all 

 events, tlie difference between them and those on which gonangia were present is verj- 

 remarkable, and it is difficult to see how, after they have attained the form descrijjed, they 

 could undergo such modification as would convert them into the fertile phylactocarp. The 

 two forms, however, may be of different sexes, and be lioth equally destined to carry 

 gonangia. 



Lytocarims spcctdb'dis comes near to Aglaophenia rostrata of Kirchenpauer, a species 

 which Kirchenpauer, who has not seen its gonosome, places in his section Mucrorhynchia. 

 The present species, however, is a mi;ch stronger form, and witli longer hydrocladia. 

 The hydrocladia, moreover, are alternate in Lytocarpus spectahilis, while in Aglaoplienia 

 o'Ofif rata they are described as opposite. 



Dredged at Zamboanga, Philippines, 30th January 1875, from a depth of 10 flithoms ; 

 also at Station 186, Torres Strait, September 8, 1874; lat. 10° 30' S., long. 142° 18' E; 

 depth, 8 fathoms; bottom, coral sand. 



Lytocarpus longicornis, Busk, sp. (PI. XIX. figs. 4-G). 



Pliimnlarin hnujicornis, Busk, Voyage of tlie "Rattlesnake," vol. i. p. 399, 1852. 



Trophosome. — Colony attaining a height of about three inches ; stem fascicled, irregu- 

 larly branched, supporting closely set pinnately arranged alternate monosiphonic ramuli, 

 which are themselves destitute of hydrothecse, l)ut give ofi" all along their length the very 

 short hydrotliecfe-bearing ramuli, which are close set, alternate, about one-twentieth of 



