1918.] N. Annandale: Slielh from Mesoiwtamia. 167 



Genus Bullinus, Adanson. 



1757. Bulinus, Adanson, Voy. Senegal, Coquillages, p. 5, pi. i, figs. 



1S15. BaUinas, Oken, Lelirbuch Natunjesch. Ill, ji. 'M):i {fide Hcdk^v). 



1830. Isidora, Ehrenberg, Symh. Phyn. II (unpaged). 



1802. Ididom (in part), Kiistcr, " Die Gatt. Limnaeus," etc., in Chemnitz's- 



Conch. -Cub. (ed. Kiister), ]>. 69. 

 1SS6. Physa (in part), Clessin, " Limnaeiden," in Chemnitz's 6'0Hc/t.-C«6. (cd. 



Kiister and Dunker), p. 236. 

 1917. Bullinus, Hcdlcy, Eec Austr. Mus. XII, p. 3. 



As this genus has now assumed a certain practical sanitary import- 

 ance it may be well to discuss its synonomy and systematic position. 

 It was originally described, from a AVest African form, by Adanson in 

 1757. He spelt the name with one " 1," but as he derived it from 

 " bulle " or bulla was evidently in error in so doing.^ Apart, therefore, 

 from any question of date, or from the fact that Adanson did not desig- 

 nate the species, Oken in 1815 was justified in changing the name to 

 Bullinus. Oken's work is inaccessible to me, but 1 gather from recent 

 writers that he merely adopted Adanson's description without seeing 

 his species. This description is clear and adequate ; the figures that 

 accompany it, though a little crude, illustrate the form of the shell and 

 the external anatomy of the animal with sufficient accuracy. They prove 

 that in the species known to him, which was described by Bourguignat 

 in 1856 as Physa senegalensis, the mantle did not extend over the shell 

 and that the tentacles were filiform. These are characters which separ- 

 ate the living Bullinus from the living Physa at a glance. 



In 1830 Ehrenberg erected for certain Egyptian and Syrian forms 

 a new genus, which he called Isidora or the " Gift of Isis." He appears 

 to have been ignorant of Adanson and Oken's genus and his description, 

 which is fairly full both in reference to the shell and to the external 

 soft parts, coincides closely with Adanson's. Moreover, the first two of 

 the three species'^ he assigned to Isidora {I. hemprichii, I. brocchii and 

 I. forskalii) are probably no more than varieties or phases of Bullinus 

 contortus, which closely resembles B. senegalensis except in the poor 

 development of the columellar callus. Isidora, therefore, seems to me 

 to be an absolute synonym of Bullinus.''^ Germain,^ however, treats 

 it as a subgenus of that genus in his recent list of the molluscs of Syria 

 and Palestine. 



Pelseneer {op. cit., 1906) places Bullinus with Planorbis in the family 

 Planorbidae, which he defines thus : " Visceral mass and shell sinistrally 

 coiled ; inferior pallial lobe very prominent and transformed into a 

 branchia ; tentacles tapering." Planorbis he distinguishes thus : " shell 

 discoid ; branchia not folded " : Bullinus thus, " shell ovoid with 

 prominent spire ; branchia folded." There is never any difficulty in 

 distinguishing the flattened discoid adult shells of Planorbis from those 



^ He says, " Je donne Ic nom de Bulin a un petit coquillagc d' cau douce 



Cetto denomination m'a paru kii convenir, parcequo I' animal pendant sa vie nage presquo 

 continuellcment a fleur d'eau, et qu'apres sa mort sa eociuille ilotte comme uno petite 

 bulle d'air transparentc." 



- The third species [i.e., the tliird to be described) I . forslcal ii , is quite distinct. 



^ Hedley {op. cit., 1917) revives the name Isidora for certain Australian species 

 in supersession of Isidordla, Tate ; but in view of what is said above this cannot stand. 



* Germain, Ball. Mus. Hist. Nut. {Paris) 1912, p. -±50. 



