ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 41 



give the appearance of serration on its side under a f objective. On 

 the inside of this joint, close to its base, is a curved enlargement, and 

 on the top a prominent, horny, knot-like plate. 



Glands in the Maxillae of Tegeneria domestica, Blackwall.* — 

 These glands, which seem hitherto to have escaped notice, are also 

 described by Mr. F. M. Campbell. Their apertures are on the inner 

 side of the median line of the upper face of each maxilla, where they 

 commence to incline towards the mouth. The external form consists 

 of a ring, averaging in adults "005 mm. in diameter, enclosing a 

 raised disk, in the centre of which is the opening leading to a narrow 

 cavity, from which runs the duct, gradually increasing in size until it 

 terminates in an elongated bulbous point. Similar organs are found 

 in some Linyphiidte, Thiridiidse, SalticidaB and Epeiridae, but they are 

 distributed at the side of the maxillse close to the mouth in a cup-like 

 cavity, as shown in a drawing from an Epeira similis Blackw. Some 

 of the ducts often become chitinous. The number of glands increase 

 with age. Mr. Campbell found one on the first exuvium of two species 

 of Tegeneria domestica, two on the second, and 80 on an adult female 

 of the same species. 



5. Crustacea. 



Heart of Decapod Crustaceans.f — A detailed experimental study 

 of the heart's action among the larger Crustaceans has been pub- 

 lished by Prof. F. Plateau. With the aid of Marey's device, and the 

 use of the recording cylinder in the Ghent Physiological Labora- 

 tory, he has obtained a valuable series of tracings by means of the 

 graphic method. The form and structural relations of the heart are 

 sufficiently explained. The movements of the heart are recorded as 

 they occur : (1) in health, (2) when influenced by electric stimuli, 

 (3) when exposed to changes of temperature, (4) in a state of asphyxia, 

 and (5) under the operation of eight selected poisons. Eunning 

 comparisons are instituted between the effects of these poisons in 

 Crustaceans and Vertebrates, with the result of showing fewer dis- 

 crepancies than has hitherto been supposed. The innervation of the 

 heart, and the part played by the pericardium, are also fully con- 

 sidered. This memoir is quite indispensable to all workers in the 

 same field. We can offer no abstract of its contents ; the author's 

 own summary covers six pages. Due references are made to other 

 investigators. 



Development of Fresh-water Macroura.^ — Dr. P. Mayer describes 

 the first seven stages in the post-embryonic metamorphosis of Palce- 

 monetes varians. He figures the more characteristic phases succes- 

 sively presented by the paired appendages, the fore-end of the 

 carapace, and the telson ; of the whole animal (bird's-eye or profile) 

 views in four stages are shown. Without the aid of these figures his 

 memoir could not be well epitomized. It must be studied in connec- 



* Journ. Linn. Soc. (Zool.), xv. (1880) pp. 155-8 (5 figs.). 



t Arch, de Biol., i. (1880) pp. 595-695 (2 pis.). 



X MT. Zool. Stat. Neapel, ii. (1880) pp. 197-221 (1 pi.). 



