REPORT ON THE HYDROIDA. 41 



Lijtocarpus racemtferus, n. sp. (PL XIII. ). 



Tropliosome. — Colony attaining the height of about twelve inches ; stem fascicled, 

 much and irregularly branched, main branches all directed towards one side of the stem ; 

 hycbocladia alternate, scarcely exceeding one-tenth of an inch in length. Hydrothecte 

 rather deep, margin serrated, teeth blunt ; intrathecal ridge well marked, situated near 

 the fundus of the hydrotheca ; mesial nematophore adnate to the walls of the 

 hydrotheca for nearly their entire height, and then continued as a short, blunt beak, 

 which scarcely overtops the hydrotheca and has both a terminal and a lateral orifice ; 

 lateral nematophores slightly overtopping the hydrotheca. 



Gonosome. — Phylactocarps in the form of long racemes, laden with gonangia, spring- 

 ing from certain branches of the tropliosome at points near the origin of the branches 

 from the stem, and there taking the places of the proximal four or six hydrocladia, con- 

 sisting of a series of internodes having every internode provided with one median and two 

 lateral spines, each of the proximal five to eight internodes carrying also an ovate pedun- 

 culated gonangium. 



Lytocarpus racemiferiis is an exceedingly beautiful species. The direction of the 

 principal branches from one side only of the main stem give it a habit not usual among 

 the Plumularidiv. The phylactocarps, with their pedunculated gonangia, form elegant 

 racemes, grouped near the proximal ends of the branches, where they replace the 

 hydrocladia of this part of the branch. Towards its distal end the Ijranch carries the 

 ordinary unmodified hydrocladia, which are continued to its extremity. 



The phylactocarps are, in the present species, of much morphological significance, and 

 must be viewed as hydrocladia modified by the suppression of the hydrothecse, whose 

 places are taken towards the proximal end of the phylactocarp by the gonangia, and 

 whose mesial and lateral nematophores have undergone but little change, and are 

 represented liy the three spines carried by each internode. These spines retain their 

 essential character as nematophores, and are each provided with a terminal oblique 

 orifice. Several of the more distal internodes are destitute of gonangia and carry only 

 the spines. 



The gonangia are supported on rather long peduncles, which spring from Ijetween 

 the bases of the two lateral spines, and are subtended, by the mesial spine. The 

 gonophore occupies the centre of the gonangium, from whose walls it is separated by a 

 clear space, across which may be seen a wreath of highly refringent spherules, by which 

 the summit of the gonophore is encircled. The sex could not be determined with 

 certainty. 



Dredged ofi' Bahia. Depth 10-20 fathoms. 



(ZOOL. CHALL. EXP. — PART XX. — 1883.) U 6 



