334 Dr. & the Rev. S. Graham Brade-Birks on 



short, proximal] y directed ridge of the same nature arises 

 from a similar position on the internal border of the lobe. 



Hob. Bakewell, wild, in a well-wooded Carboniferous 

 Limestone district, under a stone. 



Type. Slides 1275 and 1276, tube 1277, Brade-Birks 

 collection. 



It seems a convenient opportunity to give a diagnostic key 

 to the females of the genus Brachychceteuma, as follows: — 



la. Posterior lobe (of the" cyphopodite") lack- 

 ing a pair of definite circular thickenings 

 of chitin 2. 



1 b. Posterior lobe furnished with a pair of [Birks. 



definite circular thickenings of chitin . . B. melaaops, Brade- 



2 a. Posterior lobe with a marked median 



elevation 3. 



2 6. Posterior lobe without a marked median 



elevation B. quartum, nobis. 



3«. Posterior lobe with a small median eleva- 

 tion and well-marked lateral folds of [Brade-Birks. 

 chitin B. bagnalli, Verhoell* et 



3 b. Posterior lobe with a large and outwardly 



directed median elevation, but lacking [et Brade-Birks. 



lateral folds of chitin B. bradece, Brolemann 



In the males of the genus it seems probable that develop- 

 ment of the telepodite of the anterior gonopods runs parallel 

 with the development of the posterior lobe of the "cypho- 

 podite" in the vulva of the female. If that is really so, we 

 should expect that when examples of the male of B. qu.artu.rn 

 are found, the telepoditic elements of the anterior gonopods 

 will be similar to those of B. bradece and B. bagnalli — perhaps 

 slightly less complicated; we should not expect the complex 

 condition of the telepoditic horns found in B. melanops. In 

 the species known previously the coxal prolongations of the 

 anterior gonopods have been useful diagnostic features, and 

 by analogy we should expect them to differ in B. quartum 

 from those of the other species and to be simpler in form than 

 in any of them. Thus, they should most closely resemble 

 the coxal prolongations of B. bagnalli*. The syncoxite of 

 the same gonopods appears to be a fairly constant feature, 

 and so it is to be expected that in this character and in the 

 disposition of the pseudoflagella the male of B. quartum will 

 agree with the other species. 



* The coxal prolongations might, for example, be broader distally and 

 less elevated than in B. bagnalli. 



