138 THE NAUTILUS. 



ON THE SOFT ANATOMY OF £. (MICRABIONTA) HUTSONI. 



BY H. A. PILSBRY 



The animal is purplish-black, with gray mantle-edge. The sur- 

 face is finely and evenly granulose. There is a weak impressed line 

 on the ridge of the tail, and a pair of contiguous dorsal grooves, 

 scarcely noticeable except between the tentacles. Foot-margin very 

 narrow, hardly differentiated. The sole is conspicuously tripartite 

 in color, the sides being purplish or slaty-black, while the middle 

 field is of a much paler gray tint. The pale area is somewhat wider 

 than the dark sides. 



The genitalia, fig. 6, show a very short penis, swollen basally, an 

 epiphallus of about the same length or somewhat larger, and a 

 flagellum longer than either. The long retractor muscle is inserted 

 on the epiphallus, and distally on the lung floor. At the base of the 

 vagina a well-developed dart sack (d. s.) is inserted ; on each side of 

 its base enter the ducts of the mucous glands, which ascend as high 

 as the dart sack and then descend, their flattened, glandular portions 

 being bound to the vagina and atrium. The general relations of the 

 dart sack and mucous glands are shown diagramatically in fig. 8. 

 As usual, the two glands are unequal. The spermatheca is ovate, 

 on a long, slender duct. Length of penis 2 mm. ; of epiphallus 2.8 ; 

 flagellum 4 mm.; length of spermatheca and duct 16.5 mm. 



The right ocular retractor passes between the $ and $ branches 

 of the genitalia. 



The general features of the alimentary tract are as usual in the 

 Helices. The crop is long, the salivary glands equally lengthened, 

 lying on the upper side of the crop, and concrescent throughout their 

 length. 



The jaw is of the usual arcuate shape, with only three ribs, grouped 

 in the median third (fig. 7). 



The radula has 17,10,1,10,17 teeth (pi IX, fig. 5). The cen- 

 tral and lateral teeth have simply mesocones without side cusps. 

 The marginal teeth have the ectocones developed, and in the outer 

 ones the larger cusp is bifid. I noticed no teeth with the ectocone 

 bifid. The transition from lateral to marginal teeth is quite gradual. 



The venation of the lung is faintly outlined with gray pigment. 

 The kidney is about half as long as the lung, and nearly twice the 

 length of the pericardium. 



