WORMS, ETC. 515 



4 Gen. Poh/stemma (Ehrb.) Oerst. with nine species. 



|3. Oculi 8-16, biseriati. 



5 Gen. Nemertes (Cuv.) Oerst. with twenty-eight species. 

 Among others Oerstedt places here the worms described as 

 Polia, Meckelia, Notospermus, Tubulanus. 



y. Oculi four. 



6 Gen. Tetrastemma, Ehrb. with thirteen species. 



(3.) Corpus lineare-oblongum depressum, utrinque requa- 

 liter obtusum, fissime respiratorise distinctse. 



7 Gen. Cerebratulus, Ren. with two species. 



Fam. II. AMPHIPOKINA. Tubi cibarii utraque apertura 

 terminalis opposita. 



8 Gen. Amphiporus (Ehrb.) Oerst. with one species. Of 

 the species described, twenty-one belong to the coast of 

 Denmark, amongst which, fourteen quite new species occur. 



Rathke (Nov. Act. Acad. Nat. Car. &c., t. xx. p. 231) 

 has given the diagnosis of the Borlasia striata, previously 

 described by him, as follows: oculis 16 (aut 18?); corpora 

 gracili, subdepresso ; striis longitudinalibus nigresceiitibus 

 et subflavis alternantibus. To this is also added a new 

 species, viz. Borlasia rufa : oculis 6 ; facie superior! coiivexa 

 rufa, inferiore plana flavescente. Ratlike could not pro- 

 cure, in a state sufficiently perfect to allow of their diagnoses 

 being determined, two species of Meckelia, which, like the 

 M. somatotomus described by Leuckart, were able to dis- 

 member themselves with facility. Besides these worms, 

 Ratlike has designated another, also found on the coast of 

 Norway, under the name of Ramphogordius lacteus, pro- 

 bably belonging to the Gordiacese. Its very slender 

 cylindrical body terminates anteriorly in two minute pro- 

 cesses representing a proboscis, between which the oral 

 aperture is situated. Lateral depressions, organs of sense, 

 and an opening for the passage of the long vermiform organ 

 are wanting. The intestine, which is adherent to the abdo- 

 minal cavity, presents posteriorly several longitudinal folds, 

 and the abdominal nervous system is composed as in 

 of two lateral chords. 







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