TIII5 ANATOMY OK M lOGALATUACTUS — KESTKVKN. \->l 



The lUernx {ut.) is a large uncoiled tube with very thick 

 glandular walls, lying in the mantle cavity, on the right side 

 close to the body. The anterior end, which communicates 

 directly with the exterior through the genital aperture, is on a 

 level with the anus ; the postei'ior end is continued up the coil 

 for a short distance on the right side of the nephridium. This 

 end is probably a blind c;iecum, for it is unlikely that the oviduct 

 opens into it ; rather would the oviduct pass forward below the 

 nephridium and open into the uterus at the posterior end of the 

 mantle cavity. The glandular masses which are attached to the 

 wall of the uterus, and occupy the greater part of its cavity, 

 resemble pieces of tallow candle ; these masses are arranged in 

 longitudinal rows. 



The mass of egg capsules has been figured by Hedley in his 

 " Studies on Australian Mollusca " from material forwarded him 

 from Bundaberg, Queensland, by Dr. T. H. May.* 



III.— ANATOMY OF MEGALATRACTUS MAXIMUS, 

 Trvon. 



1. External Features and Pallial Complex. 



(PL xL, fig. 5.) 



The shell has I'ecently been redescribed and figured by Hedleyf 

 in the paper already referred to. 



The protoGonch (Fig. 121) is present in only one of the 

 many specimens at m}' command; it consists of about two smooth, 

 rounded whorls of equal diameter. It is not 

 defined from the succeeding neanic structure, 

 but, as in M. aruanus, the sculpture of that portion 

 of the shell ascends on to the protoconch and 

 fades out so gradually that the actual line of 

 extinction cannot be found. The nucleus has been 

 cast from my single example, and the two whorls 

 described are the homologue of the six and a half 

 angulated whorls of the protoconch of the last -pm 121 

 species. 



The operculum (PI. xxxix., fig. 7) is similar to that of JI. 

 aruanus except that the ridge described as being on the right 

 side of that operculum is absent from this. 



The foot and body also agi^ee with the last species in shape, 

 difiering only in being smaller and flecked with brown instead of 

 black. 



* Hedley— Proc. Linn. Soe. N.S. Wales, xxv., 1900, p. 508, pi. xxv., f. IS. 

 + Hedley — Aust. Mus. Mem. iv. , 1903, p. 374, pi. xxxviii. 



