220 PROCEEDINGS QF THE NATIONAL MUSEUM. vol.50. 



If this view is correct, the specific name used here is the wrong one. 

 Von Drasche examined the material for both species. On the other 

 hand, Molin (18G0«) groups these species in two different groups 

 in his monograph of the genus Spiroptera, regarding S. Tnediospiralis 

 as armed and S. chr'iso ptera as unarmed. In view of the fact that 

 modern pai'asitologists have confused Arduenna strorigylina and 

 Physocephalus sexalatus from swine in recent years, it would not be 

 surprising if two different species looked alike to von Drasche. Ac- 

 cordingly, S. medlosplraUs^ which is the one of the two species in 

 question which has the characteristic six lateral alae and is the one 

 reported from Dasyprocta agouti.^ is transferred to Pkysocephalus^ 

 leaving the possible identity of Splroptera chHsoptera to be deter- 

 mined, if possible, by a reexamination of the original material or a 

 study of new material from the hosts in (juestion. 



Physocephalus mediosplralls is described as having a head with 

 four tubercles in cruciform arrangement and with pointed apices, and 

 with an orbicular, large, bare mouth. This hardly conforms to the 

 generic characteristics of Physocephalus^ but in view of the agree- 

 ment on other points it seems likely that further study would result 

 in a better statement of the lip and mouth structure which would 

 conform with the generic characteristics. 



SialifaixiLily uiicertain. 



ANALYTICAL KEY TO UNPLACED SPECIES OF SPIRUEIDAE. 



1. Found in urinary bladder Spiroptera ratti, p. 221. 



Not found in urinary bladder 2. 



2. Adult worms witb 4 lateral alae in cruciform arrangement. 



Spiroptera quadrialata, p. 221. 

 Adults or larvae without lateral alae 3. 



3. Adult worms with a bitid tail ; found in liver Filaria Mflda, p. 221. 



Adidts without a bifid tail, or larvae; not found in liver 4: 



4. Adult worms found in tlie body cavity Filaria comca,p. 222. 



Larval, or probably larval, woi-ms 5. 



5. Undeseribed species found in esophageal nodules Spiroptera Jtystrichis, p. 222. 



Not found in esophageal nodules 6. 



6. In abdominal cavity, stomach, walls of stomach, and in cecum of Scar- 



turus tetradacii/lus (Dipiis tetradactylus). 



Nematoideum dipodis-tctradactyli, p. 223. 

 Not reported from Scarturus tetradactylus {Dipus tetradactylus) 7. 



7. Undescribed species from stomach of Mus species {Mus minimus). 



Spiroptera species von Linstow, p. 223. 

 Described species from cysts in walls of digestive tract of rat. 



Spiroptera species Gerstaecker, p. 223. 



It is quite possible that some of the species listed in this key are 

 not properly referable to the Spiruridae or even to the Filarioidea. 

 In the absence of adequate data, the judgment and authority of the 



