^§ 161, 162. 



THE ANNELIDES. 



17.5 



CHAPTER VIII. 



ORGANS OF SECRETION. 



§ 161. 



Many Annelides are covered with a mucus which is secreted by small, 

 simple follicles situated in the skin.<^' 



The calcareous tubes of the Serpulini, appear to be secreted by a collar 

 surrounding the first segment of the body.*-* It is not yet decided that 

 the leathery tube in which many other Branchiati are concealed/^* is 

 secreted by an analogous organ. 



Those Capitibranchiati which form tubes with grains of sand, bits of 

 shells, &c., have, perhaps all, an opening close behind the mouth upon the 

 ventral surface. This opening is in connection with many glands situated 

 at the anterior extremity of the body, which probably secrete a substance 

 for the gluing together of the materials of these tubes. ^*' 



CHAPTER IX. 



ORGANS OF GENERATION. 



§162. 



The Annelides reproduce partly by a transverse fissuration, and partly 

 by a sexual apparatus. 



1 Similar muciparous follicles are arranged in 

 curved rows with the llirudiiiei, upon both the ven- 

 tral and dorsal surfaces, giving the skin a granu- 

 lated aspect ; see Brandt, Med. Zool. II. p. 2i4. I 

 have seen similar groups of follicles with the larger 

 Lumbricini.* 



'■i The secretion of the calcareous matter occurs 

 here probably as upon the border of the mantle of 

 MoUusks. 



3 Sabella, Onuphis, and Chaetopterus. 



i As secreting organs of this glue, Rathki has 

 correctly described four yellowish glands situated, 



* [ § 161, note 1.] Leydlg {Siebold and KoHi- 

 ker^s Zeitsch. 1849, i). 109) has described with PU- 

 cicola, Clepsine, Nephelis, and other Ilirudinei, 

 cutaneous glands. These consist of an infundibu- 

 Uform sac, which exactly resembles a nucleated 

 cell, from which passes off a long, tortuous duct. 



with Amphitrite, upon the ventral surface of the 

 first and second segment of the body, and 

 opening by a common canal at the first seg- 

 ment ; see Danzig. Schrift. loc. cit. p. 71, Taf. V. 

 fig. 6, aa. fig. 2, d. With TerebeUa, and Sa- 

 bella, the two glands near the cephalic extremity, 

 are perhaps of the same nature. Grube, however, 

 thinks them male genital organs ; see, Zur Anat. d. 

 Kiemenwurmer, p. 31, Taf. II. fig. 12, y.; and 

 Milne Edward.'!, Ann. d. Sc. Nat. X. 1838, PI. X. 

 n. PI. XI. fig. 1, h. fig. 2, f. 



With Piscicota, these are situated in the cephalic 

 and pedal shield, hut in Clepsine, and Neplielis, 

 they are also present in the skm throughout ; see 

 loc. cit. Tuf. VIII. fig. 23. This structui-e is re- 

 markable from its resemblance to some of the cuta- 

 neous glands of the higher animals. — Ed- 



