ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ' 309 



New Trematode from Australian Poisonous Snakes. — AVilliam 

 NicoLL {Parasitology^ 1918, 10, 290-3) describes DoUchopera macalpini 

 sp. n., which, like D. parvula, seems to have its normal habitat in the 

 cesophagus, trachea and lungs of snakes. J. A. T. 



Structure and Development of Cladorchis. — Feed D. Weidman 

 i^Parasitology, 1918, 10, 267-79, 1 pL, 2 figs.) deals with Cladorchis 

 {Stichorchis) subiriqitPtrus Rudolphi, from the ctecum of the beaver. He 

 ■describes the external features, the alimentary, reproductive, muscular, 

 and excretory systems. Special attention is directed to the pre- 

 oesophageal sphincter, the oesophageal musculature, the heavy ventral 

 subcuticular musculature, the slight branching of the young testes, the 

 late development of the yolk glands, and so on. It is probable that 

 this Trematode is a commensal as much as a parasite. J. A. T. 



Liver-rot.— C. L. Walton {Parasitology, 1918, 10, 232-66, 5 figs.) 

 has studied the occurrence of this disease in the Aberystwith area. 

 There is a marked coincidence between the distribution of clay and 

 Limnsea truncatula, and of L. truncatula and Liver-rot. Drought and 

 severe frost work against the snails. Rainfall and its distribution 

 throughout the year is the most important factor governing the increase, 

 spread, and infectivity of the snail. The ova may develop even after 

 the egg-masses have dried down to a hard scale. Roadside ditches are 

 very frequently inhabited by infected snails, and drainage from them 

 may be the cause of cases of rot. Cercarise of Distomum hepaticuni 

 were obtained from L. truncatula practically throughout the year, but 

 not from snails measuring less than 4 • 5 mm. Seventy cercarite were 

 given off naturally, within forty-eight hours, from one specimen 

 measuring 7 mm. in length. A few cercaria3 resembling those of 

 D. hepaticum were obtained on one occasion from L.peregra. J. A. T. 



Regeneration in Planaria maculata. — J. M. D. Olmsted {Journ. 

 Exper. Zool., 1918, 25, 157-77, 14 figs.) has studied the regeneration 

 -of triangular pieces cut from the side. They will regenerate heads at 

 right angles to the original long axis if the following conditions are 

 fulfilled : — (a) the point of the intersection of the two cut edges must 

 lie at or near the old median axis of the worm ; {b) the angle between 

 the cut edges must be 90° or less ; and (c) the cut edges must be of the 

 same length. Under all other conditions the old polarity is most 

 •evidently unchanged. If the piece is small, it may regenerate a head 

 only, but the position of this head shows the tendency to retain the old 

 polarity. Numerous special facts in regard to the regeneration of 

 triangular pieces are stated ; the general result is the possibility of 

 retaining polarity even in extreme cases. J. A. T. 



Incertse Sedis. 



Life-history of Dicyemids. — Aug. Lameere (Bull. Soc. Zool. France, 

 1918, 42, 122-6) finds that there are five successive generations : — 

 (1) an asexual immigrant generation of " founder-nematogens " ; (2) 

 a sedentary asexual generation of " primary nematogens," which are 



