3i8 



BULLETIN OF THE BUREAU OF FISHERIES. 



significance, if any, is possessed by it. The ventral surface is further ornamented by a dark bluish- 

 gray band bordering the heart-shaped shield. 



The following note appears on the reverse of the original station label in the handwriting of Dr. 

 W. K. Fisher and affords important information regarding the appearance of this species in life (colors 

 according to Ridgway's "Nomenclature of Color"): "Tentacles, chromatophores burnt sienna, yellow 

 ocher, and light red. Eye: pupil transparent, iridescent purple, blue, and emerald green; iris reddish 

 burnt sienna. Body (except wings and outer test) iridescent orange, yellow, solferino, green, crimson, 

 purple. Chromatophores of outer test burnt sienna and sepia." 



Measurements of Stoloteuthis (Iridoteuthis) iris. 



Total length exclusive of tentacles 



Medio-dorsal length of mantle 



Medio-ventral length of mantle 



Width of body 



Width across fins 



Extreme length of fin 



Length of same fin at base of attachment. 



Median length of ventral shield 



Dorsal-ventral diameter of body 



16 



Length of head 



Width of head 



Length of — 



Dorsal arm 



Second arm 



Third arm 



Ventral arm 



Right tentacle (left tentacle missing) . 



mm. 

 4 



Type. — Catalogue No. 214312, United States National Museum [S. S. B. 31]. 



Type locality. — The type and only specimen of the species known was taken in 153 to 142 fathoms, 

 A Ibatross station 3832, off the island of Molokai, bottom of brown mud and sand. 



Remarks. — The sex of the single specimen is unknown, as owing to the brittle texture of its tissues 

 it was deemed inadvisable to attempt to pry the arms far enough apart to ascertain any further details 

 of structure or possible evidences of hectocotylization. It is very possible that the specimen is not 

 quite adult, but its characteristic features have nevertheless attained a high development. 



Perhaps the most distinctive features are the extreme development of the dorsal commissure unit- 

 ing the mantle to the head, and the immense ventral lobe. The former feature is carried to a much 

 further extreme in this species than in either 5. leucoptera or in S. nipponensis, which are the only 

 other described species of the genus, while in the latter respect the only near approach is the Nectoteuthis 

 pourlclcsii of Verrill. According to information furnished me by Dr. Ad. Naef, 5. nipponensis differs 

 from the other species mentioned in important anatomical characters, as well as in its size and general 

 aspect, and must henceforth be known as Sepiolina Naef. Its exact systematic position still seems a 

 matter of more or less uncertainty, although Naef refers it to the Sepiolina. All three of the remain- 

 ing species, 5. leucoptera, S. iris, and N. pourtelesii, are characterized by the possession of a conspicuous 

 pigmented shield on the ventral surface similar to that above described, have large fins, and are delicate 

 gaily colored creatures of doubtless similar habits. N. pourtelesii, however, stands quite alone in hav- 

 ing the dorsal border of the mantle entirely free, and 5. iris likewise is in many ways very different 

 from its congener. Because of this fact it also has recently been made by Naef the type of a separate 

 genus, Iridoteuthis, but because its most important characters (nuchal commissure, ventral shield, 

 webbed arms, etc.) are shared equally with Stoloteuthis s. s., I believe their probable relationships 

 are for the present expressed better by grouping them together. The distinctive features adduced by 

 Naef are the integumentary fold in the nuchal region, the large head, protruding eyes, immense fins, 

 ventral protraction of the mantle, and unequal arms, but none of these features seem sufficient of 

 themselves to be regarded as of more than subgeneric value. A more complete knowledge of either 

 S. iris or S. leucoptera than we at present possess might, however, indicate differently. 



