X ANATOMY OF AGHATINID^. 



PSEUDACHATINA (vol. xvi, p. 205). Soft anatomy unknown. 



ATOPOCOCHLIS (vol. xvi, p. 218) has been dissected by Fur- 

 tado. The jaw (pi. 1, fig. 7, after Furtado) is thin, arcuate, 

 densely plieatulate vertically. Radula with 100 rows of 54. 

 34.20.1.20.34.54 teeth each. Centrals narrow, obsoletely tri- 

 cuspid, the cusp not overhanging. Laterals with the meso- 

 cone large, broadly rounded, the small ectocone also rounded ; 

 marginals with the entocone weakly developed (pi. 1, f. 6, 

 after Furtado). 



Genitalia (pi. 1, figs. 8, 9, after Furtado). Penis with the 

 usual basal ring-muscle (g p.) pierced by the vas deferens; 

 the latter inserted at the apex, with the retractor muscle, which 

 is a branch from the ocular retractor (fig. 9). The sperm- 

 duct is free from the vagina, but unites with the uterus. 

 The vagina is ovoid and muscular, the duct of the sperma- 

 theca being inserted very high. The albumen gland is small 

 (specimen collected in December). 



PSEUDOTROCHUS (vol. xvi, p. 219). The anatomy has been 

 investigated in P. alabaster by Semper, and P. auripigmen- 

 ium by Schako. In P. alabaster the foot and the eye-tentacles 

 are long and narrow (pi. 1, fig. 2, after Rang) . The foot has 

 no lateral margination, and the sole is undivided. There are 

 two body-lobes on the left side of the mantle, small and very 

 far apart. The kidney is double the length of the pericar- 

 dium, band-like. Genitalia (pi. 1, fig. 1, after Semper) 

 simple, without accessory organs. The duct of the sperma- 

 theca is not very long, 'but is inserted very high on the uterus. 

 The vas deferens inserts at the apex of the penis, but passes 

 through a circular muscle encircling the lower part of the 

 penis. The retractor muscle of the penis is apical, and so 

 placed that it passes through the loop formed by the vas def- 

 erens. It is short and wide, and inserted on the columellar 

 muscle. The jaw has fine striation. Radula (pi. 1, fig. 3) 

 with 80 to 100 teeth in the transverse rows ; middle tooth very 

 small, with tridentate cusp ; lateral teeth broad-cusped, with 

 a small blunt cusp at the outer side. In P. auripigmentum, 

 Shako found the jaw (pi. 1, fig. 4) and teeth (pi. 1, fig. 5) 

 to be like those figured by Semper for P. alabaster, except 

 that the central tooth is not tricuspid. 



