ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 251 



mass has more distinctly the character of a nerve-sheath than in the 

 other forms described. The body parenchyma is largely represented 

 by a special tissue, which forms a very strong layer extending from 

 the pharynx along the whole dorsal surface ; the constituent cells are 

 greatly elongated in a vertical direction, and their ground-substance 

 contains a number of refractive yellowish granules. 



Cercaria s^inifera, from Planorhis corneus, stands very close to 

 C. echinata. 



Entozoa of Sharks and Rays of the Bay of Naples.* — Dr. L. 

 Orley reports that the Selachians are generally poor in entozoa, that 

 they are ordinarily found only in the intestine, that Cestodes are more 

 common than Nematodes, and these than Trematodes. Seven round- 

 worms are mentioned, of which Ascaris affinis (from Mustelus Isevis) 

 and Spirojyterina elegans (from the rare HexancJms griseus) are new. 

 Distomum megastomum is the only Trematode mentioned. The 

 Cestodes are remarkable for their small size, never being more than 

 10 cm. in the largest shark. Orygmahothrium dohrni (from Heptanclius 

 cinereus) is new ; the commonest species is Acanthohothrium coronatum. 



Pelagic Animals from Fresh-water Pools in Alsace and 

 Lorraine.! — Dr. 0. E. Imhof gives a list of the pelagic animals which 

 he has found in various fresh-water pools in Alsace and Lorraine. In 

 addition to seven species of rotifers which are already known he has 

 found two which appear to be new ; these are a species of BracMonus 

 which is intermediate between B. haJceri and B. poly acanthus ; he 

 proposes to call it B. lotharingius ; the generic position of the other 

 remains at present undecided, but it approaches Triarthra and 

 Pohjarihra. 



Tube of Melicerta.l — Mr. T. S. Smithson describes an unusual 

 form of tube made, in two cases which he observed, by Melicerta ringens. 



The young Melicerta began by building half a course in the usual 

 way with apparently solid pellets, but instead of continuing to do so, 

 it suddenly commenced to heap up, in a most erratic manner, pellets 

 of the ordinary shape, but composed of transparent gelatinous matter 

 with a few particles of carmine imbedded in it, giving the tube a 

 somewhat mottled appearance. The walls of the tube, owing to the 

 loose way in which they were made, were about double the thickness 

 of those constructed in the usual manner. 



The author suggested that want of material is the primary cause 

 of this mode of building, while Mr. A. D. Michael thought there was 

 some uncertainty as to whether the variation resulted from the fact 

 that the trough did not contain suitable matter for building, but only 

 some kind of flocculent matter likely to swell, or whether it was a 

 variety as to the building of the tube. It is a matter of frequent 

 observation that, in spite of the extreme regularity of the tube under 



* Temn. Fuzetek, ix. (1885) pp. 97-126 (Hungarian), 216-220 (German) 

 (1 pi.). 



t Zool. Arizeig., viii. (1885) pp. 720-3. 



i Journ. Quekett Micr. Club, ii. (1886) pp. 221 and 244-5. 



