42 SUMMARY OF CURRENT RESEARCHES RELATING TO 



membrane with some circular fibres, a basal membrane, and a layer of 

 long cylindrical epithelial cells with short cilia. The ureter is sinuous 

 with internal folds of epithelium. It is covered by a thick muscula- 

 ture with a thin layer of external longitudinal fibres and a thick layer 

 of circular muscles. Within this the wall shows" a basal membrane, a 

 chitinogenous epithelium, and an internal intima of chitin with folds 

 and minute denticulations. 



Crop of Mallophaga.*— Bruce F. Cummings finds that the crop 

 presents three types of structure in Mallophaga. It is just an expan- 

 sion of the lower part of the oesophagus in Amblycera ; it is a large 

 diverticulum in most Ischnocera ; it is a long narrow-necked sac in 

 Trickodectida?. In Amblycera the crop-teeth are characteristic in the 

 different genera ; in Trichodectidse they are absent ; in other Ischnocera 

 there is a characteristic patch in the anterior csecum of the crop. 

 Plateau suggested that proventricular teeth in general are used for 

 straining, not for mastication. In Amblycera it seems unlikelv that 

 there can be any masticatory function, for the teeth are long, slender, 

 and sharp, and their development is not correlated with powerful 

 muscular folds. In the Ischnocera the short scattered teeth mav be of 

 assistance in clearing out the food which collects in the anterior csecuni. 



Oogenesis in Podurids.f— L. de Winter has studied in Podura the 

 development of the ovarian cells before the differentiation of the oocytes 

 into ova and vitelline cells, and in the course of this differentiation. 

 Finally the ovarian cavity is found to be occupied with full-sized ova 

 and some masses of vitelline cells and some liquefied residue. The 

 vitelline cells are nothing but abortive ova, which are unfavourably 

 situated. In the first phase of the nutrition of the ova, there is an 

 accumulation of fatty material ; in the second phase albuminoid material 

 is secured. In the second phase the ova occupy the surface of the 

 ovary; they absorb nutritive materials from the hgemoccel ; they utilize 

 material from the ovarian cavity ; they engulf vitelline cells and absorb 

 products of the disruption of vitelline' cells. The author compares the 

 ovary of Podura with that of other insect types. 



$• Prototracheata. 



New Forms of Peripatus.^— C. T. Brues gives a preliminary account 

 of Peripatus manni sp. n., which is closely related to P. sedgwichi Bou- 

 vier from the Caribbean coast of South America, and P. dominkse 

 Pollard subsp. haitiensis subsp. n. Both were collected in Haiti bv 

 W. M. Mann. 



5. Araehnida. 



Study of Trichotarsus osmise.§ — A. Popovici-Baznosanu has in- 

 vestigated the life-history of this mite which occurs in the cells of 

 Osmia, one of the solitary bees. He describes the ovum, the hexapod 



* Ann. Nat. Hist., xii. (1913) pp. 266-70 (3 figs.). 



t Arch. Biol. Soc, xxviii. (1913) p. 197-227 (4 pis. and 3 figs.). 



X Bull. Mus. Zool. Harvard, liv. (1913) pp. 519-21. 



§ Arcb Zool. Exper., lii. (1913) Notes et Revue, No. 2, pp. 32-41 (12 figs.). 



