ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 417 



placed in a large glass. Next morning it was found inside the nest, 

 and there it was treated by the spider with great care. In the sunshine 

 she brought out the clump and exposed it to the rays ; in the evening 

 she took it back. This went on for about three weeks. Thereafter the 

 mouth of the nest was closed by a delicate web, which was gradually 

 strengthened. But the spinner left a hole for dragging in food. At a 

 certain date even the hole was closed up, but when the observer made 

 an opening a fortnight afterwards, he found that the young had hatched. 

 The details of the protective device are carefully given ; its efficacy 

 is even more thorough than our summary suggests. 



Stigmatic Organ of Nymph of Ornithodoros megnini. * — E. Of. 

 Wheler describes a remarkable organ found in a tick, identified as 

 this species, which was removed from the ear of an American visitor at 

 Cambridge. The organ in question consisted of two protuberances, 

 placed in the position of stigmata, one at each side of the body. Each 

 was truncate, perforated by a hole at the tip, and from this hole a 

 pointed organ could be protruded and withdrawn. 



Larval Hydrachnida.f — Chas. D. Soar has a note on the parasitic 



young of the common water-mites, and the hosts on which they occur. 



He is of opinion that the larvae remain attached to the same host for 



a whole season, from the summer of one year until the spring of the 



next. 



t. Crustacea. 



Paranuclei in Cells of Digestive Gland of Crayfish.^ — P. Vigier 

 discusses the body described by Nussbaum in 1881 under the name 

 of NebenTcern, and by others as paranucleus, noyau accessoire, and 

 " parasome " (Henneguy). In an actively secreting cell it lies near 

 the nucleus, or between the latter and the free surface ; it is due to 

 the nucleolus, which migrates into the cytoplasm to contribute to the 

 elaboration of the secretory product. The best name for it, according 

 to the author, would be pyrenosomc. Ehumbler has regarded the 

 nucleolus as a mass of reserve-material for nuclear consumption ; 

 Haecker has called it excretory ; the author considers it as " a body 

 formed from a differentiation of the chromatin, and capable of migrat- 

 ing as a whole, or of giving off a portion of its substance into the cyto- 

 plasm, to furnish to the latter the materials necessary for the elaboration 

 of the characteristic products." 



Spermatogenesis in Sacculina.§ — 0. Duboscq describes the lineage 

 of spermatic cells, — spermatogonia, spermatocytes, spermatides, and 

 spermatozoa. The cells arise indifferently from the peripheral cells or 

 from those of the vas deferens. These cells form, as far as may be, a 

 lining to the cavities produced by the disappearance of other cells of 

 the same origin which have undergone degenerative hypertrophy (hya- 

 line degeneration with karyorhexis). A hypertrophied cell does not 

 divide unless amitotically ; after death it forms nourishment for the 

 spermatic cells. 



* Journ. Quek. Micr. Club, 1901, pp. 61-2 (2 figs.). 



f Tom. cit., pp. 65-G (1 fig.). 



j Cornptes Rendus, exxxii. (1901) pp. 855-7. 



§ Arch. Zool. Expe'r., ix. (1901) Notes et Revue, pp. xvii.-xxiv. (9 figs.). 



Aug. 21st, 1001 l 2 F 



