74 o General Notes. [September, 



Gephyrea and the Echinodermata, but that the former represents a 

 distinct class allied to the Annelids and divisible into an armed 

 (Echiurida) and unarmed (Sipunculidae) group. In his elaborate 

 account of the anatomy of Si/witcitlits audits, Dr. Andreae {Zeits. 

 Wissen. Zoologie, xxxvi, 1 88 1) expresses similar views as to the 

 relations of the Gephyreae. 



On the other hand, Dr. Vejdovsky has studied very carefully 

 Sternaspis, a form intermediate between the Gephyrea and Chae- 

 topods. His memoir appears in the Denkschriften of the Vienna 

 Academy. He concludes that there are four natural orders of 

 the class Annelides : I. Hirudinea ; 2. Oligochata ; PolycJncM ; 

 and 4. Gephyrea. He derives the fir< t two from the Discodrilida, 

 and the other two from Sternaspis ; the Discodrilida he considers 

 form an offshoot from the Oligochaete stem, which descends into 

 the Amedullata, which, with Sternaspis, have their common ori- 

 gin in the Turbellaria, which in turn are derived from the Cce- 

 Ienterates. He also believes that the larvae of the Chaetopods and 

 Gephyrea are formed on the same type, and that in Echiurus there 

 is a true segmentation of the body. 



Nervous System in Tape-worms.— The Cestodes, or tape- 

 worms are usually described as having no nervous system. On 

 investigation by transverse sections, Dr. A. Lang finds in the 

 Tetrarhynchi a band-shaped cerebral mass with two longitudtaal 

 trunks which arise from the brain, and which give off lateral 

 branches, the separate fibers of which enlarge here and there into 

 very long and large ganglion cells. In Amphilina, an unjointed 

 Cestode, the nervoue system has a not inconsiderable resemblance 



>pical Society, 



Dr. Lang sums up the state of our knowledge as to the nervous 

 system of the other Cestoda. Ttenia perfoliita has a better de- 

 veloped nervous system than the rest of the Taetiiadae ; the anas- 

 tomosis or cerebrum contains nuclei and fibrils, gives off two 

 lateral primary trunks, and completed resembles in structure the 

 same parts in the Nemertinea. Tcenia solium, with others, has 

 three cords on either side. In the ISothriocephalida the water 

 vessels are on the outer side of the longitudinal nerves, and here 

 also the anastomosis is oncave anteriorly; in the Ligulida the 



trunks lie & outside the water vessels,' and are approximated to- 

 wards one another in the anterior region of the body. 

 Simroth's Nervous Sy 



AND FRESH-WATER MoLLU 



the programme of the Realschule of the second order at Leipzig, 

 and is an able discussion of the principal types of nervous sys- 

 tem in these mollusks, with remarks on the physiology of loco- 

 motion. The plate is an excellent piece of work. 



