366 



Mr Cobb, On Free-living fresh-water 



The annexed illustrations of some known species together with 

 their formulae will serve to make the application of this decimal 

 system perfectly clear. (Figs. 2 and 3.) 



a, lip. 



b, cephalic seta. 



c, pharynx. 



d, eye. 



e, lateral organ. 

 /, nerve-ring. 



g, excretory pore. 



h, ampulla. 



i, posterior end oesophagus. 



j, cardia. 



k, ventral gland. 



I, blind end of testicle. 



m, egg. 



n, intestine. 



o, o, o, diatoms in intestine. 



p, vulva. 



q, junction of vas deferens and ejaculatory duct. 



r, one of the caudal glands. 



s, ejaculatory duct. 



t, proximal end left spiculum. 



u, posterior part of ejaculatory duct. 



v, shaft, left spiculum. 



w, rectum. 



x, anus. 



y, accessory piece. 



z, terminus. 



Fig. 3. Monhystera diplops. 



8 mm. 



15- - M' 



1-8 3- 



3-3 



3- 



I, male worm. II and IV, head and anal region of the same worm more highly 

 magnified. Ill, portion of the body of a female, showing the vulva. 



I think it would not be too much to expect reviewers to always 

 include the decimal formula in even the briefest of notices if 

 authors would take the trouble to give their measurements in that 

 form. If such a custom could be brought into vogue it would 

 constitute, it seems to me, a considerable improvement in helmin- 

 thological literature, for we should then have, even in the briefest 

 notices in the Zoological Record, Zoologische Anzeiger and other 

 similar publications considerable highly condensed information in 

 a form that would not take up too much of their valuable space. 



The present paper might be noticed for instance in somewhat 

 the following fashion : — 



Cobb, Proc. of the Cambridge Philos. Soc, Vol. xn. 1904, "Free- 

 living Fresh-water New Zealand Nematodes"; describes new species 

 as follows : — 



Mermis Novae Zealandiae 



•0 1-7 4-7 <48-' 26 ? ._ , __ 



; = 28' to 38" mm. 



