22 OPISTHOBRANCHIATA OF BRAZIL 



from these elevations. The largest one of the basal impressions 

 thus left measured 6.0 mm. in length by 5.0 mm. in width. The 

 teeth are arranged in a sort of quincunx in about six transverse 

 rows, the larger ones occupying the middle and posterior por- 

 tion, and in front of these the smaller ones are alternately ar- 

 ranged. The largest of these teeth measured 4.0 mm. in height. 

 In the contracted state of this portion of the stomach, the apices 

 of these teeth meet in the center of the lumen and fit closely 

 together, thus nearly closing the opening. 



Succeeding this first triturating stomach is a somewhat 

 wider and longer, much thinner walled division of the alimentary 

 canal, the "second triturating stomach" of Mazzarelli. Its walls 

 are much less muscular than those of the first stomach, being of 

 practically the same thickness as those of the ingluvies. Instead 

 of bearing numerous small teeth as in those Mediterranean 

 species studied by Mazzarelli ('93), the teeth are reduced to a 

 single series arranged in a transverse row, about midway of the 

 length of the organ. These teeth are very small and readily 

 dehiscent; their basal impressions are nearly round in outline, 

 and about 0.7 mm. in diameter. There are seven such impressions 

 in the first specimen dissected, six and eight in others, arranged in 

 a transverse row, and occupying about one-half of the total cir- 

 cumference of the whole organ. The remainder of the lining of 

 the second stomach is entirely smooth. 



Posterior visceral complex. The hinder portion of the second 

 stomach is situated between the two anterior lobes of the large 

 liver, thence passing rather abruptly into the intestine. The poste- 

 rior visceral mass is made up of the liver, the intestine and the 

 hermaphroditic gland, and is broadly conical in general form, 

 the apex being directed posteriorly, and the elliptical base lying 

 against the posterior part of the stomach and partially inclosing 

 it. It is covered by a delicate membrane of connective tissue, 

 the peritoneal lining of the pseudo-coelom. The intestine is very 

 thin walled, and is filled with finely divided detritus of algal 

 nature. It describes a series of complicated loops upon the liver, 

 in the surface of which it is imbedded. The intestine enters the 

 liver at its lower border, passes backward, thence upward and 

 forward describing a long loop upon the upper surface of the 

 liver toward its right side, to return again to the left, from which 



