<§168. 



THE ANNELIDES. 



181 



bricini at this period, is of an analogous nature. It is also composed of 

 numerous cutaneous glands, closely aggregated, and extending completely 

 over many segments of the body.*** The secretion of this collar is like that 

 ■observed with the Hirudinei, probably for the formation of cocoons. But 

 these cocoons difler from those of the Hirudinei in having the place of their 

 opening prolonged into a long, narrow neck.'^' 



§ 168. 



The Eranchiati resemble the Arthropoda in their annulated body, their 

 distinct head endowed with organs of sense, the structure of their nervous 

 system, and the development of their locomotive organs ; but, from the 

 .simplicity of their locomotive apparatus, and the complete absence of cop- 

 ulatory organs, they would be carried towards the Zoophytes. 



Here the sexes are separate, and the genital organs of both the Capiti- 

 branchiati, and Dorsibranchiati, appear as simple glandular bodies, ovaries 

 or testicles, which project from the ventral surface into the cavity of the 

 body between the fasciculi of the cutaneous muscle.*'* At the sexual period, 

 they are filled with eggs, or spermatic particles, although at other times they 

 can scarcely be seen.*-' 



Neither the testicles nor the ovaries have excretory ducts which open 

 upon the surface of the body. The sperm and eggs escape into the cavity 

 of the body, which, during this period is thereby filled throughout.*^' 



It is possible that the scarcely visible orifices said to be concealed be- 



i Saenuris, Tfais, &c.; see Gruithuisen, loc. cit. 

 Tab. XXXV. fig. 5, b.b. 



5 With the large species of Lumhricus, each co- 

 coon has from one to six eggs (Zy. Dufour, Ann. d. 

 Sc. Nat. XrV. 1828, p. 216, PI. XII. B. or, Froriep's 

 Notiz. No. 472, 1828, p. 149, fig. 13-16 ; and Hof- 

 meister, De vermibus quibusdam, Tab. I. and Die 

 Arten aus der Familie, &c., p. 16, 25, 42). With 

 the smaller Lumbricini, as with Saenuris, Euaxes, 

 Ifais, &c., the cocoons contain nearly always five 

 to eight eggs (Dugis, loc. cit. XV. PI. VII. fig. 5, 

 JVaia). Most of these cocoons have appendages 

 liy which they are attached to vegetables and other 

 bodies. Hojf'meister (Die Arten aus der Farn. &c. 

 p. 42, fig. 9, c.) has figured a very remarkable 

 liusk-shaped cocoon of a uew species, Criodrilus 

 iacuuni. 



1 See Treviranus, Zeitsch. f. Physiol. III. 1827, 

 p. 165, Taf. XIII. fig. 17, 18 (^Aphrodite); Ratkki, 

 De Bopyro et Nereide, p. 39, Tab. II. fig. 12, 1. 

 (TVerei.s), and Danzig. Schrift, loc. cit. p. 66, Taf. V. 

 fig. 6, hh. fig. 11, aa. {Amphitrite) ; Grube, 

 Xav Anat. d. Kiemenwürmer, p. 16, Taf. I. fig. 1, 

 2, m. {Arenicola), p. 44, Taf. II. fig. 6, y. z. (Eu- 

 nice); also, Nov. Act. Acad. XX. p. 201, Tab. X. 

 fig. 13, 15, m. {Ammotrypane). Rat/ike^s and 

 Grube^s opinion upon the presence of both male 

 and female organs with the same individual is only 

 an uncertain supposition, founded upon no histo- 

 logical examination of the parts. 



'■i This condition of the genital glands after the pro- 

 creative season, is the reason why, as yet, we pog- 

 sess so few facts as to their structure. Most ob- 

 servers, and among them Ralhhe and Grube, are 



* [§ 168, note 2.] According to Quatrefo^es 

 (Ann. d. Sc. Nat. X. 1848, p. 46) the sexes are sep- 

 arate with the Hermella. Both the testicle and the 

 ovary consist of a delicate areolar tissue adherent to 

 the inferior internal surface of the general cavity of 

 the body. These genital organs are evidently tern- 



16 



of the opinion that the Branchiati, like the Lumbri- 

 cini, are hermaphrodites. But (^uatrefages, from 

 his knowledge of the development of the spermatic 

 particles, has recognized separate sexes with the 

 most different species, thus : Terebella, Sabella, 

 Aricinella, Nephtyx, Syllis, Glycera, Eunice, 

 Sigalion, Phy/lodoce, Nereis, And Aphrodite; 

 see Comp. Rend. XVII. 1843, p. 423. But before 

 this, Stannius had concluded that the sexes were 

 separate with Arenicola, from a difference in the 

 contents of the cavity of the bodies of different in- 

 dividuals (Muller's Arch. 1840, p. 375). The 

 glands at the cephalic extremity of the Branchiati 

 which live in cases, and which Grube has regarded 

 as male genital organs, are certainly not such, for 

 they occur with both sexes, and do not change in size 

 during the pnxireative season. (See § 161, note 4.) * 

 3 According to ^uatrefages (Compt. rend. 

 XVII. 1843, loc. cit.), the parent sperm-cells 

 leave the testicle before the formation of the 

 spermatic particles, which occurs in the cavity of 

 the body. This is confirmed with Arenicola, by 

 Stannius (Muller^s Arch. 1840, loc. cit.). Ac- 

 cording to Krokn (fViegmann's Arch. 1845, I. p. 

 182), the eggs and the spermatic particles, with Al- 

 ciopa, are developed free in the visceral cavity, 

 without the intervention of special organs, ovaries 

 and testicles. Frey and Leuckart (Beitr. &c. p. 

 88) think they have observed the same fact with 

 Nereis, Sy/lis, Phyllodoct, Aonis, Ammotry- 

 pane, Ep/iesia, Hermella, rermilia, Fabricia, 

 and Spirorbis ; they speak of the presence of ova- 

 ries and testicles in certain Aimelides (Aphrodite, 

 Arenicola) as the exception. 



porary, for they are not found in many individuals, 

 having, probably, quite disappeared from atrophy 

 after the procreative period. This fact should be 

 remembered in the study of the genitalia of other 

 Annelides. — Ed. 



