Two Species of Brachychaeteumidse. 83 



millipede belonging to tlie Microchordeumidse, and therefore 

 more closely related to Brachychseteumidae ; it is smallish, 

 has 28-30 body-segments, and the lateral keels are vestigial. 

 Macrosternodesmus palicola and Ophiodesmus albo nanus are 

 our two smallest examples of the true square-backed milli- 

 pedes of the family Polydesmidse ; they are both white ; the 

 former is the smaller and more slender, has 19 body-segments, 

 and the lateral keels are irregular (notched or " toothed ") as 

 in Polydesmus and Brachydesmus, whilst Ophiodesmus has 

 20 body-segments, with the lateral keels entire as in Ortho- 

 morpha. Monacobates is a Protoiulid, very slender and small, 

 like a short piece of animated wire. 



Brachychaeteuma m el an ops. 



Swanage (Jurassic formation). Sligmatogaster subter- 

 raneus, common ; Macrosternodesmus palicola, frequent; the 

 recently discovered Ophiodesmus albonanus, both sexes, 

 several ; and Monacobates tenuis, rare. 



Torquay District (Middle Devonian). Whilst collecting 

 in this district no species were, found commonly or in company, 

 but the following were noted while searching for Brachy- 

 chceteuma : — St igmatog aster, rare and apparently replaced by 

 Chcetecln/lene vesuviana, sl species so far only known from 

 South Devon in our country ; Macrosternodesmus, Ophio- 

 desmus, and the Monacobates, rare. 



Brachychseteuma bagnalli. 



Gibside, Co. DURHAM (Carboniferous). Stigmatog 'aster •, 

 rare; Macrosternodesmus and Monacobates, in numbers. The 

 original example of B. bagnalli was found here, but has not 

 yet been rediscovered, and a solitary female example of 

 Chordeumella is also recorded. 



Newcastle-ON-Tyne (Carboniferous). Haddiick's Mill : 

 Sligmatogaster, not uncommon; Macrosternodesmus and 

 Monacobates, frequent ; Chordeumella sp., once only. Fen- 

 ham : Sligmatogaster, Macrosternodesmus, and Monacobates 

 were all found under the single log harbouring the Fenham 

 colony of B. bagnalli. 



Hexham (Millstone Grit). Monacobates occurred in very 

 large numbers, together with a few of a similar creature — 

 Nopoiulus palmatus, — but only two examples of Macrosterno- 

 desmus were found. A Geophilid, curiously resembling 

 Stigmatogaster, proved to be Clinopodes linearis ,araire southern 

 form that I had not previously met with. 



