TO PROCEEDINGS OP THE ACADEMY OF [1880. 



The central nervous system was as above mentioned, and also the 

 eyes (their nervi optici rather long), and the otocysts (the number of 

 the otokonia about one hundred). The bulbus pharyngeus as usual ; 

 on the tongue sixteen rows of teeth, farther backwards eighteen rows 

 of developed and four of younger teeth ; the total number of rows, 

 thirty-eight. The plates as above ; the length of the median plates 

 005 to 058 mm. ; the height of the anterior large lateral plates 

 about 0.14 mm., of the posterior about 0.17 mm. ; the number of den- 

 ticles on these plates mostly fifteen to twenty. The vesica fellea wa? 

 at the left side of the pylorus. 



S. L. hystricina, Bergh. 



L. hystricina, Bcrgh, Mai. Untersuch., 1. c, 1878, p. 614, Tab. Ixviii. 

 fig. 17-23. 



Color cocrulescens. 



Denies laterales margine interno denticulati sed non usque ad 

 apicem. 



Habitat. Oceanum Pacificum (insula Kyska). 



One specimen of this species was found by Dall, at Kyska Island 

 (Aleutians), on rocky bottom, at a depth of ten fathoms, in June. 

 1873. According to Dall, the color of the living animal is bluish. 



The specimen preserved in spirits was 9.5 mm. in length, reached 

 a breadth of G mm., and a height of the true body (without the 

 papilUe) of .3.5 mm. ; the breadth of the foremost part of the foot 

 was 5.3 mm., the height of the rhinophoria was about 2.1 mm., of the 

 branchia about 1.2 mm., of the dorsal papilla^ 1.2 mm. The color 

 was uniformly whitish. 



The form was oval, the back not very convex. The head rather 

 large, formed like a velum, that is radiately folded, and has its side 

 parts connected with the ends of the anterior margin of the foot ; in 

 the middle of the hinder part of the under side of the velum is a trans- 

 verse slit, in which the small mouth-pore opens. The opening of the 

 rhinophor-holes was nearly round, with the margin rather thin, here 

 were three papilla? of the same kind as on the back ; the rhinophoria 

 stout, the club with about twenty leaves. The back covered all over 

 with mostly stout, club-shaped papilhv, apparently set without order, 

 and extending nearly out to the very margin of the mantle, which is 

 thin and has on the upper side smaller, cylindrical or club-shaped 

 papilhe. The papilht all firmly adherent to the skin, the spicules shin- 

 ing through all over on the back and in the papillae. The branchial 



