The Non-Marine Mollusca of Portuguese East Africa. 163 



Although the last record is plausible, I suspect that it should refer to 

 one of the two foregoing species. Junod mentions that his shells have two 

 longitudinal bands on the base, a feature very unusual in mozamhicensis, 

 but nearly always present in dubiosa and usagarica. 



Rhachidina spilogramma (Mts.), 1860. 



1860. Bulimus spilogrammus Mts., Mai. Blatt. vi, p. 214, pi. 2, fig. 9. D.F. 

 Hab. L. Marques. Tette (Peters) ; Mtisherra R. Valley (Cressy). 

 A beautiful little species, easily recognisable from the author's figure. 



Genus Rhachistia, nov.* 



Type Buliminus rhodotaenia von Martens (Conch. Cab. 1901, p. 750, pi. 

 110, figs. 12-13). 



This new genus is rendered necessary for the reception of the group of 

 species, usually with brightly painted, rather large and solid shells, which 

 cannot now be retained in Rhachis with R. punctata. 



The shells are usually broader than those of Rhachis, and grow to a far 

 greater size, becoming more solid in maturity than they do in Rhachidina ; 

 I have not yet found their peristome expanded, as in the last-mentioned 

 genus. 



The radula is of a specialised arboreal type, as will be seen from the 

 figures of Sarasin f and Thiele.J It differs considerably from that found 

 in any of the preceding genera, although in some respects the anatomy of 

 Rhachistia seems to be very similar to that of Conulinus. 



Judging from their radula, abortiva and bewsheri Morel., erlangeri Kob., 

 burnayi Dhrn., histrio Pfr., moluensis Kob,. sanguinolenta Barcl., sticta 

 Mts., and zonulata Pfr. belong to this genus, while from the shells alone 

 it probably includes, inter alia, gomezi, Sow., venustus Morel., neuricus Rve., 

 picturatus Morel., ganalensis Kob., trichrous Mts., pallens Jonas and 

 aldabrae Mts. 



Rhachistia rhodotaenia (Mts.), 1869. 



var. andradensis Germain, 1918. 



1918, Rachis (Rachis) rhodotaenia Mts., var. andradensis Germ., Bull. 

 Mus. Paris, xxiv, p. 155, D. 



Hab. L.^Marques. Andrada (Vasse). 



* paxisTos, cut or cleft out of. 



t Land-Moll. Celebes, 1899, pi. 31, fig. 305. 



j Arch. f. Moll.-k. liii, 1921, pi. 4, fig. 1. 



