ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 243 



measure 38 by 23 jj.. There is no indication of the origin of this remark- 

 able form, which appears to be most closely allied to D. personatum. 



Some of the results of M. Poirier as to the histology of the nervous 

 system are traversed, the connective lamellae which were said to embrace 

 it not being apparent to M. Moniez ; a careful description of the course of 

 the nerves is given ; some of the ganglion-cells are stated to attain the size 

 of 50 by 30 /x ; it is suggested that in some Trematodes we have a primitive 

 arrangement of the nervous system. The parenchyma is regarded as being 

 formed of a connective tissue with more or less close bars, the liquid which 

 fills the interspaces coagulating under the miiucnce of reagent-; it is this 

 coagulated matter which has given ris. to the false interpretation of cells 

 filled with protoplasm and touching on . another ; the justice of this criticism 

 may be seen by a careful study of sections of the common fluke. 



Nervous System of Tape-worms.* — As the results of his investigation 

 of the central nervous system of Tsenise, Herr G. Joseph notes — (1) that 

 the two cerebral ganglia are in many cases ( T. transversalis, T. rophalocera, 

 hare) connected, not by a single dorsal commissure, but by two, separated 

 by matrix and muscle-processes ; (2) that each cerebral ganglion is triple, 

 consisting of a median and two smaller (dorsal and ventral) ganglia, 

 separated by muscle processes, as is best seen in T. crassicolUs ; (8) that 

 in the bladder-worm, before the evagination of the hooks, the central 

 system exhibits six equatorial ganglionic masses, which afterwards form a 

 nerve-ring by the growth of bipolar processes. 



Syndesmis.f — M. P. Francois makes some corrections in the account 

 given by Mr. Silliman in 1881 of Syndesmis, a new Turbellarian ; it is not 

 ectoparasitic, but is found in abundance in the intestine of Stronfjylocentrotiis 

 lividus ; the cilia of the epidermic cells are of the same size on the dorsal 

 and ventral surfaces, and not larger below ; the muscular system is formed 

 by a system of well-developed dorsoventral fibres, and a few poorly 

 developed longitudinal muscles in the anterior ventral region. There is 

 no body- cavity ; the digestive apparatus is more complex than has been 

 supposed, but there are not a large number of testes, but only a pair, though 

 these are provided with csecal appendages ; the uterus contains not one egg, 

 but an ovoid shell which contains from two to thirteen eggs. The author 

 corrects various errors as to the details of the female generative, apparatus, 

 into which he thinks that Mr. Silliman has fallen, but he agrees with his 

 predecessor in the view that Syndesmis represents an intermediate form 

 between the Trematoda and the Turbellaria. On account of its habitat he 

 proposes to call it *S^. echinorum. 



5, Incertse Sedis. 



Studies on Rotatoria. it — Dr. C. Zelinka describes two new species of 

 the genus CalUdina, C. symhiotica and C. leitgebii, which are found livino- 

 on Hadula complanata, Frullania dilatata, and other Hepatic^ ; they are not 

 true parasites, but "free space-parasites," dependent with the moss for 

 rain and dew ; they are widely distributed through Germany and Austria. 

 Their anterior end is suddenly retracted and slowly extended, their move- 

 ment is leech-like, and swimming is only rarely to be observed. Sixteen 

 longitudinal folds are to be found on the back and sides, but are absent 

 from the ventral surface. The matrix of the cuticle is a syncytial 

 hypodermis. 



* Ber. 59 Versammlg. Deutsch. Naturf. u. Aerzte, Berlin, 1S86. Cf. Biol. Ceutialbl., 

 vi. (1887) p. 733. f Comptes KenHus, ciii. ( 1SS6) pp. 752-4. 



X Zeitschr. f. "Wiss. Zool., xliv. (1886) pp. 396-506 (4 pis.). 



