WORMS, ETC. 513 



* 



surface, peculiar filamentous organs projecting, which were 

 certainly connected with the sexual function. In Cleps. 

 complanata and tessulata, the first-formed ova escape late- 

 rally into the back, by which, at last, a sort of zone or 

 girdle of ova is formed, from which the animal withdraws its 

 cephalic extremity, its body forming a sort of shield over 

 the group of ova. Cleps. tessulata, marginata, and compla- 

 nata remain lying motionless upon these groups of ova, but 

 subsequently carry about with them, on the abdomen, the 

 progeny when extruded from the ova ; but Cleps. hyalina, 

 Carenee, and bioculata carry about with them, not only the 

 young, but also the ova. In another paper (Archiv, 1844, 

 Bd. i, p. 370), Miiller has described the anatomical differ- 

 ences between Clepsine tessulata and marginata. 



Grube has selected the development of the ova of Clepsine 

 for the subject of ample researches (Untersuchungen, iiber 

 die Entwicklung der Anneliden. Heft, i, 1844), from which 

 we learn that Clepsine complanata deposits usually five to seven 

 ova, enveloped in a very transparent, soft, saccular egg-case ; 

 whilst in Cleps. bioculata there are only three or four, and 

 in Clepsine marginata, only one ovum in each capsule. The 

 egg-cases (nidamental capsules) are glued, by a peduncle, to 

 water-plants, and continue hanging thereon, whilst the 

 young, when extruded, attach themselves to the belly of the 

 mother. The ovi-position, as well as the preparation of the 

 capsules, was observed by Grube to be performed in the 

 same way in Clepsine as it is known to be in Nephelis. He 

 has also described the internal structure of the sexual organs, 

 but was unable to satisfy himself, whether the Clepsina re- 

 ciprocally impregnate each other, or whether their ova are 

 developed in consequence of self-impregnation. 



NEMERTINI. Oersted has systematically arranged the 

 division of the Nemertini (Entwurf einer systematischen 

 Eintheilung und speciellen Beschreibung der Plattwiirmer; 

 Kopenhagen, 1844, p. 76), which must be acknowledged to 

 be the more deserving of our thanks, since the literature 

 respecting these so much neglected worms is very scattered, 



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