444 Bulletin American Museum of Natural History [Vol. LIT 
The number of valid species remains undetermined; P. tanganyicen- 
sis probably includes most of those described. The different contour of 
P. livingstoniana, P. subtriangularis and P. bourguignati probably denotes 
specific or subspecific rank for these forms. 
Two small species collected by Stappers, P. ortmanna and P. 
stappersi, show no beak sculpture following the circular glochidium. This 
character has not hitherto been used for the discrimination of species, 
but it appears to be more important than variations of outline depended 
upon by Bourguignat for this purpose. 
Simpson considered this group to be near Lampsilis, especially the 
section then comprising U. tenuissimus Lea. This American species, 
however, is in a late stage of tooth degeneration, and such resemblance 
as exists is doubtless due to convergence. Germain’s view that Pseudo- 
spatha belongs to the Mutelide is supported by the examination of a 
dried specimen of P. ortmannz, which shows a strong connection of the 
mantle between anal and branchial orifices. Unfortunately the gills 
had been almost entirely macerated away before drying up. Whether 
the genus belongs to the Muteline or to the Hyriinzx could not be ascer- 
tained. 
Pseudospatha tanganyicensis (EK. A. Smith) 
Plate XLV, Figures 1-3 
Spatha tanganyicensis E. A. SmitH, 1880, Proc. Zool. Soc. London, p. 350, PI. 
XxxI, fig. 8 (only). E. v. Marrens, 1883, Sitz. Ber. Ges. Naturf. Fr. Berlin, p. 71. 
PELSENEER, 1886, Bull. Mus. Hist. Nat. Belgique, IV, p. 111. G. B. Sowmrsy, 1894, 
‘List of Shells of Lake Tanganyika,’ p. 2, Pl., fig. 19. 
Burtonia tanganikana Bouravienat, 1883, ‘Moll. Fluv. Nyanza Oukéréwé,’ p. 
20. GERMAIN, 1905, Bull. Mus. Hist. Nat. Paris, p. 260. 
Burtonia tanganyicensis EH. A. Smith. E. v. Marrens, 1897, ‘Deutsch Ost Afr., 
IV, Beschalte Weichth.,’ p. 257. E. A. Smiru, 1906, Proc. Zool. Soc. London, I, p. 184. 
Pseudospatha tanganyicensis . A. Smith, Simpson, 1900, Proc. U.S. Nat. Mus., 
XXII, p. 577; 1914, ‘Descript. Cat. of Naiades,’ p. 203. Grrmain, 1908, ‘Rés. 
Scientif. Voy. Afrique Foa,’ p. 685; 1911, Bull. Mus. Hist. Nat. Paris,-p. 441. 
Burtonia foat J. Masriuue, 1901, Bull. Soc. Philomath. Paris, (9) III, 2, p. 58. 
GERMAIN, 1908, ‘Rés. Scientif. Voy. Afrique Foa,’ p. 686, figs. 39 and 40. 
Burtonia joubertti Bourcuianat, 1886, ‘Nouv. Malacol., I, Un. et Irid. Tangan- 
ika,’ p. 40. Grrmain, 1908, ‘Rés. Scientif. Voy. Afrique Foa,’ p. 685, figs. 37 and 
38 (on p. 686). : 
Burtonia lavigeriana Bourauianat, 1886, ‘Nouv. Malacol., I, Un. et Irid. 
Tanganika,’ p. 36; 1888, ‘Iconogr. Malacol. Tanganika,’ Pl. xxrv, figs. 1-4. 
Burtonia magnifica BouRGUIGNAT, 1886, ‘Nouv. Malacol., I, Un. et Irid. Tan- 
ganika,’ p. 41; 1888, ‘Iconogr. Malacol. Tanganika,’ Pl. xxvu1, figs. 1 and 2. 
Burtonia moineti BoURGuienat, 1886, ‘Nouv. Malacol., I, Un. et Irid. Tan- 
ganika,’ p. 33; 1888, ‘Iconogr. Malacol. Tanganika,’ Pl. xxv, fig. 1. 
