71 



NOTE ON THE ANATOMY OF APERA BURNUPI, 

 E. A. SMITH. 



By WALTER E. COLLINGE. 



In 1897^ I briefly described some parts of the internal organs of 

 Altera Imniiipi, E. A. Sm., and later- I have given a similar description 

 of A. Jiatalensia, Cllge. Both these specimens had been in alcohol for 

 some years, and I pointed out how difficult it was to make out the form 

 of the various organs owing to their exceedingly brittle nature. Recently 

 I have been able to examine a further specimen of the former species, 

 and I find that my earlier description is incorrect in one very important 

 feature, viz. the male generative organs. In the specimen previously 

 examined I was unable to trace any distinct penis, and so far as I 

 could interpret the form of the terminal ducts, the vas deferens 

 seemed to open into the vestibule, the anterior portion dilating slightly, 

 and this I termed the penis (Cf. op. cit, pi. v, fig. 6 j^-)- 



In the specimen now examined I find a well developed penis, 

 which opens into the vestibule on the right side. It is a long, muscular 

 organ, gradually becoming larger distally and then tapering to a blunt 

 point. The vas deferens joins it on the inner side, nearly at its distal 

 end as a bulbous sac, and attached to the left side of this sac is a 

 small diverticulum (Fig. i, d.), possibly the homologue of the flagellum 

 common to many TedacelUdae. Passing then closely along the inner 

 or left side of the penis to the region of the vestibule, the vas deferens 

 makes a turn backward and here becomes slightly dilated. The 

 retractor muscle of the penis is very long, measuring 14-5 millim. in 

 the present specimen, whose total length is about 52 millim. It takes 

 its origin from the mid-dorsal body-wall, and is inserted in the penis 

 at its extreme distal end. 



The condition of the male organ is probably similar in A. natal- 

 ends, where I was unable to find any penis in the type specimen. 



In their beautiful work on the land mollusca of the Celebes, the 

 Sarasins express the opinion that Apera is an ancestral form o( Afopos^ 

 Simr., and that both genera are nearly related to the Testacdlidae. 

 While admitting that Apera is closely allied to this family, I am inclined 



1 Ann. Mag. N. H., 1897 (s- 6), vol. xx, pp. 221-225, ?'• v. 



2 Ann. Sth. Afr. Mus., 1900, vol. ii, pp. 1-8, pis. i, ii. 



