THE PLUMULARID.K. 31 



globular mass of sperm cells, while iu the female the ova are all on one side of the spadix. In 

 the male the spadix may break up distally into several lobular clivertirula which penetrate the 

 mass of sperm cells. 



Gonangium.fhis is to the blastostyle what the hydrotheca is to the hydranth and the 

 nematophore is to the sarcostyle, being purely protective in its nature, inclosing the reproductive 

 individual in a chitiuous capsule, the distal end of which appears to be closed in almost all cases 

 by a chitinous cap, which is finally ruptured by the passage of the sexual products. 



The gouangia in the Eleutheroplea are found most commonly along the front of the hydro- 

 cladiate portion of the stem and rather frequently on the hydrocladia, where they are usually 

 placed just below the hydrotheca'. More rarely they spring from the hydrorhiza (Plumularia 

 echinulata), although I know of no American form which exhibits this peculiarity. When grow- 

 ing on the front of the stem they are most frequently situated iu the axils of the hydrocladia 

 although they are at times thickly crowded along the entire front of the stem (Plumularia piunata). 

 In the Statoplea the gonaugia are borne rather exceptionally on the stem, as in Cladocarpux sep- 

 tatus and several species of Halicomariu, and commonly on a modified hydrocladium, as in Aglao- 

 phenia, Cladocarpus (iu part), and. Aglaophenopsis. Rarely they are borne on unmodified hydrocladia, 

 as in Nuditheca dalli and Halicornaria saccata. In some cases they are borne on nematophorous 

 appendages to the hydrocladia, as in Cladocarptix pnradisva. In many cases they appear to replace 

 hydrotheca', as in several species of Lytocarpus, and in others they are thought to take the place 

 of mesial nematophores, as in certain species of Aglaophenopsix. 



In form the gonangia are typically ovate, but there are many more or less important modifica- 

 tions. As illustrating these departures from the type form in the Eleutheroplea, the following 

 may be mentioned : The cylindrical gouangium of Antennopsis annulata (Plate XII, fig. 7), with an 

 apparently truncated end. The gonangia of Kchizotricha tenelta .(Plate IV, fig. 4) iu the shape of 

 a robust horn or cornucopia, the tip of the horn being attached to the hydrocaulus and the large 

 end containing the aperture; the oblong ovate form found in Plumularia elegant tila, with a cruciform 

 depression on the distal end: the oblong ovate form with lunate latero-terminal aperture shown in 

 Antennularia americana (Plate IX, fig. 3) ; the spinulose gonaugium found in Plumularia echiiuthitn, 

 which has the upper portion armed with long, strong, hornlike spines; the greatly elongated 

 gonaugia with distal ends produced into slender necks found in Plumularia setacea (Plate I, tig. 1 ); 

 the obovate form found iu Plumularia altitheca (Plate II, fig. 1 ) ; the globular form characteristic of 

 Schizotriclia dichotoma (Plate XV, fig. -4); the obovate structure with a pronounced operculum of 

 Plumularia styli/era Allinau; the aunulated gonangia of Phimnlarin lialerioides; and the obcouical 

 gonangia with the very wide shelflike rim around the top and branched nematophorous processes 

 shown in the remarkable species Sciurella indirisa. The gonangia of the Eleutheroplea are iu 

 general larger than in the Statoplea, and show considerable more divergence in form. They are 

 very generally armed with two or more uematophores placed on or immediately above the peduncle. 



In the Statoplea the gonangia show but little diversity in form, probably on account of the 

 greater proportion of protected gonangia found in that group. In Aijhiophenw the oblong-ovate 

 form is, so far as I know, universal. In Cladocarpus the latero-teriuiual lunate aperture prevails. 

 The gonangia are flattened and obcordate in outline in several species of Lytocarpux (Plate XXXI, 

 fig. 6). In Xuditheca they are exceedingly large and elongated, with thick chitiuous walls. 

 Finally there are the inverted cones characteristic of Halicornaria (Plate XXXIII, fig. Id). 



Structures for the protect ion of the (loiiani/ia anil their contents. In many of the eleutheroplean 

 genera and in most of the Statoplea there are special contrivances always supplied with numerous 

 uematophores, which are evidently designed to guard the important structures contained within 

 the gonangia. The term "Phylactm-aiy" 1 has been used by Allman 1 to designate any structures 

 obviously intended to serve this purpose, and it has been of great convenience in the discussion 

 of these highly diversified and interesting features of the Plumularid:e. The same writer has 

 divided the family into two groups on the basis of the presence or absence of phylactocarps, those 

 species possessing these structures being called "pkylaciocarpal" while those not possessing them 

 are "gymnocarpal.'" 



' Report ou the Hydroi.la dredged by H. M. S. Challenyer .luring the years ISTli-lsTii, p. in, I't. 1, I'lnmiilrii-idii-, 

 1883, p. 10. 



