470 SUMMARY OK CURRENT RESEARCHES BELATING TO 



wry characteristic, and there may be as many as five on one specimen, 

 not round the male genital aperture, but on the dorsal and dorso-lateraJ 

 surfaces of the cliteUar segments. 



New Leech from Egypt.*— W. A. Harding describes Placoldella 

 segyptiaca sp. n., ectpparasitic on tbe mud tortoise (Trionyx triunguis). 



" The nearly terminal mouth, the seven pairs of crop caeca, and the fact 

 that its host is a tortoise place this leech beyond doubt in the Olosso- 

 siphonid genus Placoldella (R. Blanchard, 1893)." The size of the largest 

 specimen, in a medium state of contraction, was 14 "5 mm. long by 

 5 mm. wide. 



Nematohelminthes. 



Blood Filaria in Horse.t — H. Mandel gives a description of a micro- 

 filaria which he found abundantly in the blood of a Berlin horse. This 

 is apparently the first case of the kind in a European horse. It remains 

 to be seen whether it is a casual occurrence or whether filarial cause 

 some disease the aetiology of which is still unknown. 



Oxyuris in the Appendix vermiformis.J — G-. Railliet reports that 

 out of 119 appendices he found fifty-eight with Oxyuris. In one case 

 there was a male Trichocephalus. Usually there were about ten, but not 

 uncommonly there was only one. In five cases the number exceeded 

 fifty, and one child had over a hundred. They usually rest on the 

 mucous membrane, but they may penetrate into it. No blood was 

 detected in any of them. Marked vitality is characteristic. Thus in 

 one case there was a living Oxyuris in an appendix thirty hours after 

 operation. 



Nervous System of Ascaris.§ — R. Goldschmidt completes his study 

 of the nervous system of A. lumbricoides and A. megalocephala. He 

 describes the minute structure of the glia, the nerve-fibres, and the 

 ganglion-cells, and devotes particular attention to the neurofibrils, which 

 he strongly maintains are only of the nature of cellular skeleton. One 

 of the curious individual results of a most penetrating investigation is 

 that cell 2G of the Gangl. ceph. lat. int. is present only in males. 



Platyhelminthes. 



Pearl-inducing Parasite. || — T. Southwell has made a number of 

 feeding experiments in order to determine the adult of the worm whose 

 larva; form pearls in the oyster. He has not yet found Tetrarhynchtts 

 union if actor — the adult stage suspected — in any fish in the open sea, but 

 thirty-eight were found in specimens of Ginglymostoma concolor, which 

 had been fed on oysters in an enclosure. The experiments remain 

 inconclusive ; but the strong probability is that the adult of the worm is 

 T. unionifactor, that its life-history is direct from the oyster to the fish, 

 and that the adult may occur in all Elasmobranchs that feed on oysters. 



* Ann. Nat. Hist., vii. (1911) pp. 388-9 (1 fig.). 



t Centralhl. Bakt. Parasitenk., Mi. (1910) pp. 84-7 (1 pi. and 1 fig.). 



X C.R Soc. Biol., lxx. (1911) pp. 310-11. 



§ Festschrift Richard Hertwig, ii. (1910) pp. 253-354 (7 pis. and 29 figs.). 



|| Ceylon Marine Biological Reports, v. (1911) pp. 213-15. 



