256 MRS. JANE LONGSTAFF ON NON-MAKINE 



Two individuals from Ad-Duwem have the test much thinner, the teeth 

 less strong, and the exterior a brighter green than usual ; the nacre is 

 bluish white. 



NODULARIA (CiELATURA) SOBAENSIS, Sp. nOV. 



Five specimens were taken at Soba on the Blue Nile. 



A description oi: the species by Mr. H. Preston will be found in 

 Appendix I., p. 2<d6. 



Section Lanceolaria, Conrad. 

 NoDULARiA (Lanceolaria) tbretiusoula, Pldlippi. 



TJnio teretiusctdus, Pliilippi, 1847, ' Abbildg. Beschreib.' vol, iii. p. 45, pi. 3. fig. 3. 

 Unio cailliaudi, Ferussac, von Martens, 1866, Malak. BUitt. p. 13. 

 Unio lithophagus, Parreyss in MS. 

 Unio lithophagus, Ziegler in MS. 



Only a left valve was found at Tawila on Abba Island. It agrees in form 

 with the holotype, but is smaller. It measures, long. 39*5, alt. 17 mm. 



The holotype is also from the White Nile, and measures, long. 51, alt. 21, 

 crass. 19 mm. 



This species has had the names cailliaudi and Utliopliagus bestowed upon 

 it, which have apparently only existed in manuscript, for they had not been 

 published previous to Philippics description. Von Martens gives the name 

 cailliaudi priority, though there is no certain evidence of Ferussac having 

 published it. Philippi credits the name lithophagus to Parreyss, while von 

 Martens refers it to Ziegler. N. teretiuscula is also recorded from the Bahr 

 el-Grhazal, Albert Nyanza, Nabia, and Egypt. I have seen the specimen in 

 the British Museum (Nat. Hist.) from Abu Zeit referred by Captain Flower 

 to this species, and find it belongs to the following variety. 



Var. PALLARYI, nom. nov. (PI. 18. figs. 12-14.) 



Var. lithophaga, Ziegler, Pallary, 1902, Bull. lust. Egypt, ser. iv. no. 3, p. 95. 



Diagnosis. — This variety differs from the type in being lower, more elon- 

 gated, and more pointed posteriorly, in the umbo being nearer the anterior 

 end, and in the anterior lateral teeth of the left valve beino- nearer together. 

 The valves are also much swollen. The exterior is dark brown, the nacre 

 bluish white, tinged with salmon-pink inside the umbo, and in one example 

 from Ad-Duwem this colour has spread all over the interior. 



M. Pallary is mistaken in referring this form to Unio lithophagus, Ziegler, 

 which is a synonym in manuscript of the typical name, and according to 

 von Martens (Malak. Bliitt. 1866, p. 13) has similar dimensions. I therefore 

 propose calling it after M. Pallary. 



According to my experience the variety is much more abundant than the 



