ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 295 



metridae, and they are absent in Hydrocorisre. In form like small sacs, 

 with backward directed pores, they arise as integumentary invaginations. 

 Their minute structure, their opening and closing, their oily acid secre- 

 tion (cimicin acid, C 16 H 28 2 , according to Carius), and other important 

 details are described. 



These dorsal glands show in their minute structure and in their 

 position a close resemblance to the integumentary glands of Orthoptera 

 cursoria (Blattidse and Forficulidaa), and to the protective glands of 

 Chilognatha. With both of these they are doubtless homologous. 



A Most Primitive Insect.* — F. Silvestri describes Aaajapyx vesi- 

 culosa g. et sp. n., a new Thysanuran from Italy, which is in many ways 

 the most primitive insect known, even more primitive than Projapyx. 

 It perhaps represents an early offshoot from the progenitors of the 

 Progoneata (Symphila and Diplopoda). The new genus combines in a 

 remarkable manner characters of the Symphila and Diplopoda (posterior 

 glands and ventral vesicles), characters of the Campodeidse (styliform 

 appendages of the first sternite and the form of these stiles, which 

 in Campodeidee are restricted to segments 2-7) ; characters of the 

 Japygida3 (presence of stiles even on the first segment of the abdomen 

 and the nature of the tracheal system), and characters of the Lepismatidse, 

 perhaps only secondary, (great development of the anterior part of the 

 intestine). 



Studies on Thysanura.f — K. Escherich discusses in the first place 

 the relations of the suggested genus Lepismina to Lepisma and Grassiella, 

 between which it must be dissolved. An account is then given of the 

 species of Grassiella, including three new forms from South Africa. 

 The author then describes an interesting new myrmecophilous species, 

 Lepisma emilice from Algiers, one of the peculiarities of which is that 

 the head bears in front a number of thick tufts of radiating scale-hairs, 

 each finely pinnate and curved in at the tip. In its form and in its' 

 black colour it is also notable. Three other new myrmecophilous species 

 are described. 



Development of Spermatid of Notonecta glauca.J — J. Pantel and 

 R. de Sinety describe the final stages in the spermatogenesis, from the 

 spermatocyte of the second order to the mature spermatozoon, paying 

 particular attention to the development of the idiozomic corpuscles, the 

 Nebenlcem, the blepharoplast, and the mutation of the spermatid. 



Acrosome of Spermatid of Notonecta. § — J. Pantel and R. de 

 Sinety have satisfied themselves that in this case the acrosome has an 

 idiozomic origin and is not connected, as some have supposed, with the 

 Nebenlcem. The idiozome is gradually formed, at two periods, from 

 two kinds of corpuscles, as a gradual differentiation of the cytoplasm as in 

 higher Vertebrates. There is never any real fusion of acrosome and 

 nucleus ; the nuclear membrane seems to be persistent. 



* Ex. Ann. R. Scuola Agric. Purtici. v. (19031 pp. 1-8 (1 fig.). 

 + Zool. Anz. ig., xxvi. (19031 pp. 345-66 (12 figs ). 

 X Comptes Rendus. cxxxv. (1902) pp. 997-1000 (12 tiers.). 

 § Tom. cit., pp. 1124-6. 



