NEMATOLAMPAS, A REMARKABLE NEW CEPHALOPOD. 2OQ 



circular-ovate in outline, but the terminal organs are com- 

 paratively narrow and elongate. 



The arms are unequal in length, and in one instance, that of 

 the ventro-lateral pair, this inequality is of a very extraordinary 

 nature. This arm pair is in any case the longest and their 

 basal portions much the stoutest, but furthermore each termi- 

 nates in an exceedingly slender beaded filament which when 

 straightened out is considerably longer than the entire remaining 

 portion of the animal and is devoid of suckers, though the arm 

 proper is normal in this respect. The entire arm bears a succes- 

 sion of small but heavily pigmented photogenic organs scattered 

 at various intervals along its outer margin. On the filament 

 these appear as swellings or tubercles, often half as large in 

 diameter as the filament itself, but on the basal portion of the 

 arm they become rather deeply imbedded and are not easily 

 seen except by transmitted light. Including its filament the 

 better preserved arm of this pair carries a total of thirty-one 

 photophores. The remaining arms are normal as regards their 

 extremities, but those of the dorsal and dorso-lateral pairs bear 

 each a single photophore near the tip. All the arms bear two 

 rows of small suckers, but no hooks. The order of relative length 

 is 3, 2, 4, i. 



The tentacles are about as long as the mantle, their clubs 

 little expanded and armed with four rows of suckers. Each has 

 a pale indistinct swelling in the stalk a short distance from 

 the base and a similar one a little distance below the club. 

 Except that the proximal one is situated considerably nearer 

 the base of the stalk, these swellings occupy a region analogous 

 to the position of the tentacular photophores described by Chun 

 for Thaumatolampas (1903, p. 570, fig.; 1910, p. 59, pi. 1-4) and 

 quite likely represent similar structures. 



As in Thaumatolampas also some of the more important 

 luminous organs lie within the mantle cavity and in the living 

 animal are visible only by reason of the transparency of the 

 pallial tissues. These organs are eight in number and through- 

 out are clearly homologous in the two genera. The two anterior 

 are situated one on either side of the alimentary canal just 

 back of the funnel and correspond to the anal organs of Chun. 



