52 



THE POLYPI. 



«§>4(>. 



The Campanulariae and Sertidariae produce at the end of their pedicle 

 and branches elongated sexless individuals. But in the angles of these 

 branches cells of another form, and containing many spherical individuals, 

 are developed. In these last sexual organs are formed, which, in Campan- 

 ularla genicidata, occurs without a separation of the new individuals from 

 the coralluni, while in Campamdaria gelatinosa it is after detachment has 

 taken place.''" 



§ 46. 



In the eggs of polyps both a germinative vesicle and dot may often be 

 seen. Frequently, however, both disappear at a very early period. The 

 envelopes of the egg are usually of a simple,* though sometimes of a 

 complicated structure. The spermatic particles are very active, and in 

 some species are filamentoid, in others composed of a solid body or head, 

 to which is appended a very delicate tail. Water does not appear to afiect 

 either their form or motion.'-' 



5 According to Krohn (MilUer^s Arch. 1843, p. 

 174), it is probable tliat in Cainpanularia and Ser- 

 tularia both sexes are developed in tiiis way. 

 From Ellis' description of Campanularia dicho- 

 toina (Essai sur I'Hist. Nat. des Corallines, p. 

 116, pi. XXXVIII. fig. 3), it may be concluded 

 that the females, mistaken by these naturalists for 

 eggs, separate in this way from the corallum. 

 Meyen (Nov. Act. physico-raedica. XVI. Suppl. I. 

 1334, II. 195, Tab. XXX. flg. 3, 4) has also taken 

 the raedusoid females of this species for spawn. 



[Additional note to § 45.] The series of those 

 polyps, the sexless (nurse-like) individuals of 

 which produce self-dependent, medusa-like young, 

 has been increased by several more recent re- 

 searches. See Van Beneden, Rech, sur I'embryol. 

 d. Tubulaires, 1844, pi. I. IV. (Tubularia and 

 Eudendrium) ; Sars, Faun, littoral. Norveg. p. 7, 

 Tab. I. {Podocoryna and Perigonimus) ; Du- 

 jardin, Ann. d. Sc. Nat. IV 1845, p. 257, pi. XIV. 

 XV. (various Hydrina). It is true that the de- 

 velopment of the genital organs has not been ob- 

 served in tliäse medusu-like individuals ; but they 

 have indeed in the medusiform individuals of Si/n- 

 coryne ramo.fa and Cori/ne/>"j7;7te?-Ja, and there- 

 fore it may be proper to infer that the same is true 

 of other Hydrina and Sertularina. If it is cor- 

 rect to regard as the perfect state that in which 

 the individuals resemble Meduste, and as the im- 

 perfect state thit in which they are polypoid, then 

 should we, as has been done already by many, re- 

 move these animals from the class of the Polypi, 

 and place them with the Acalephafi.* 



1 In most Anthozoa. Eggs of this kind, belong- 

 ing to Actinia, Coryne and Veretillum, have 

 been figured by fVas^ner {Wiei;inann's Arch. 

 1835, I. Taf. III. fig. 2; Prod. Hist. Geaer. horn. 

 at(|ue anim. Tab. I. fig. 1, and Icones zaot. Tab. 

 XXXIV. fig. 5, 17, 23). 



'^ With most Bryozoa the spermatic particles 

 are filamentous. Both from their size and their 



motions, they have been taken for parasites.^ 

 KoUiker (Bjitr. zur Kennt, d. Geschlechtsverhalt. 

 u. d. Saamtn. Flüssigkeit wirbellos. Thiere, p. 41, 

 Taf. II. tig. 17) has s^en the spermatic particles of 

 a thread-like form, of Fluftra carnosa, develop- 

 ing in cells, and has seen them moving in the cav- 

 ity of the )3ody. I have seen similar ones in'Crista-^ 

 tella mirahilis and Pliiinate/la campaniilata.. 

 Those which were seen by Farre (Phil. Trans. 

 1837, p. 403, pi. XXIII. fig. 5, g) in the cavity- 

 of the body of Valckeria cuscuta, and were re- 

 garded by him as intestinal worms, have an oval- 

 body, to which is attached a delicate tail. Nord-^ 

 mann (Pauiie Pontique loo. cit.) has found those of 

 Cellaria avicularia having the same form. Those 

 of Actinia have also a similar form (see Erdr 

 Müller'/! Arch. 1842, p. 301, and Kölliker, loc. 

 cit. p. 44, üg. 13). One should be careful and not 

 confound the spermatic particles with the nettling 

 organs having a similar form ; and especially as 

 the development of these last has apparently some 

 connection with that of the sexual organs (see 

 Erdl loc. cit. p. 305). Accordhig to Kölliker, the 

 spermatic particles of Alcyonidium gelatinosum 

 have a lanceolate body, with a hair-like tail (loc. 

 cit. fig. 11). 



Spermatic particles of a cercaria-form have been, 

 observeil by fVagner (Icon. zoot. Tab. XXXIV. 

 fig. 7, 12) with VeretiUum and Hydra ; by Fan 

 Beneden (Rech, sur I'urganisat. d. Laguncula,. 

 and Rech, sur I'anat. d. Bryozoaires, pi. V. in the 

 Nouv. M6m. de Bru.'ielles, &c. XVIII.), with La- 

 giincula ami H'ttodactylux ; by Ratliki {fVieg- 

 mann's Arch. 1844, I. p. 161, Taf. V. fig. 6) and 

 Sleenstriip (Untersuch, üb. das Vorkommen d. 

 Hermaphrodit, p. 66, Taf. I. fig. 18, e) with 

 Coryne ; finally by Kölliker (Nene Denkschr. 

 VIII. p. 48, fig. 20, 21, 22, 24) with Pennaria, 

 Eudendrium and Sertiilaria. In Crifiia, on the 

 other hand, Kölliker found the spermatic particles 

 perfectly filiform, t 



* [ End of additional note to § 45.] The remark- 

 able relations here spoken of, and the conjectures 

 as to the real zoological nature of the animals in 

 question, have been iiretty satisfactorily cleared up 

 by the recent researches of Agaxsiz. He has shown 

 that the Hydroid P(jlyps are not simply a lower 

 form of stemmed animals, producing at a given 

 period more highly-organized Medusa;, but that 

 they are themselves, by their structure', real Medu- 



SfB. See Lectures on Comparative Embryology, 

 1848; also Proceed. Araer. Assoc, for the Advance- 

 ment Sc. 1849 (" On the Plan of Structure and Ho- 

 mologies of Radiated Animals"), and Mem. Amer. 

 Acad. loc. cit. p. 225. — Kd. 



t [ § 46, note 2.] I have been able to trace the- 

 development and character of the si)ermatic par- 

 ticles of many of the true Polyps and the Bryozoa. 

 The developmeut occurs iu special daughter-cells, 



