19 177 



only little thickness, white, but appeared grayish yellow on account of the thin yellowish 

 cuticle. 



The form was not to be determined; at about the middle of the length of the 

 frontal shield the black eyes shone through not far form each other. The arcuate gill 

 was ll mm long by a breadth of 3 - 5 mm , and a thickness of up to 3 - 5 mm ; the number of 

 leaf-fascicles on either side was about 18; about the last fourth part of the gill was freely 

 projecting. 



The central nervous system was like that of the specimen before examined 

 by me, and so was also the case with the eyes and the olocysts. 



The length of the buccal tube was 2 mm . — The bulbus pharyngeus had a 

 length of 3-5 mm , by a breadth of up to 3 mm , and a height of up to l-5 mm . The yellowish 

 brown mandible plates (flg. 20) were separated above and below by a little interval; above 

 they were rather broad and rounded, somewhat tapering below, almost l mm long/ their 

 rather straight fore edge was finely dentate; the elements (fig. 21) formed, from behind for- 

 ward about 30 quincuncial oblique series, and were somewhat bent, angular columns of a 

 height of about up to 0"14 mm ; their upper end was dentate. The tongue was strong; the 

 yellow, tapering radula contained 38 series of tooth-plates, the 13 foremost of which were 

 incomplete ; in the radula-sheath were further found 24 series , 3 of which were not fully 

 developed ; thus the total number of series of tooth-plates was 62. In the series up to 

 25 lateral plates were found on either side of the median one '). The basal piece of the 

 plates was yellow, otherwise they were almost colourless. The breadth of the median ones 

 was - 07 mm , the height of the lateral ones up to 0"14 mm . The median plates (fig. 22 a) were 

 small, rather broad, with rather broad hook. The lateral plates with rather broad basal 

 part refolded at the edge, and rather higher and slenderer hook rounded at the end ; they 

 had all, also the innermost ones (fig. 22), smooth edges. 



The salivary glands were whitish, of a length of ll mm , reaching to the masti- 

 catory stomach, thin, tapering in the foremost half-part, and covered with fine tubercles. 



The oesophagus of a length of 9 mm , with a swelling before the cardia. The 

 masticatory stomach of the common form had a length and breadth of 6 ram . The 

 highly curved, beautiful masticatory plates had a length of 3 - 5 mm ; the upper part of the 

 body had a beautiful, chest-nut colour, inside the margin was seen an iridescent blue 

 band, and the surface, as before described, was furrowed ; the lower part of the body was 

 as usual, transparent, yellowish gray. The short part behind the masticatory stomach 

 without any widening. The greater part of the intestine was extended to a diameter of 



') In the specimen formerly examined by mo (I. c. p. 200) the number of series of tooth-plates was 70 

 (H + 26), the number of lateral plates on either side of the median one 20. 



D. K. D. Vidensk. Selsk. Skr., 6. Række, naturvidensk. og mathem. Aid. X 11. 2. 23 



