CEPHALOPODA OF THE HAWAIIAN ISLANDS. 



293 



Type. — In the British Museum (Natural History). 



Type locality. — "On the Reefs, Honolulu, Sandwich Islands;" three specimens (Challenger 

 expedition). 



Distribution. — Honolulu Reef, Oahu (Challenger, Albatross, etc.); Hilo, Hawaii (Stanford Univer- 

 sity collections); Rotuma (Hoyle); Rimatara (Wiilker); Buka, Solomon Islands (Wiilker); Stewart 

 Islands (Wiilker); Amboina (Joubin); Ceylon (Ortmann). 



Material examined. — The following 13 specimens have been examined, the majority of them being 

 rather immature: 



Although P. marmoraius appears to be a well marked, even if in no way an extraordinary species, 

 it nevertheless exhibits a considerable measure of variability. The four young individuals from Hono- 

 lulu Reef (S. S. B. 183), which I have assumed to be referable here, indicate this to a remarkable 

 degree, and it maybe possible that they are incorrectly determined; they possess a wide flattened 

 head, pale coloration, no ocular markings, and the skin varies from a nearly smooth state to one where 

 the scattered papillae are erect and bristling. The numerous small chromatophores render the surface 

 finely punctate, and a single slightly zigzag row of somewhat larger chromatophores extends along the 

 outer surface of each arm. The male in this lot is readily distinguishable by its small but well- 

 developed hectocotylus, and by the rather conspicuous enlargement suffered by the seventh and eighth 

 suckers on each of the lateral arms. The remaining suckers are rather small, a little elevated, and 

 equidistant as in the females. The measurements are surprisingly constant, as shown in the above 

 table. 



Hoyle compares this species with the Califomian P. bimaculatus (Verrill) and apparently with 

 justice, although he is undoubtedly correct in regarding the two as distinct. Specimens of the two 

 species placed together have an entirely different aspect and are not likely to be confounded. The 

 divergent pigmentation alone is entirely sufficient for the ready separation of most specimens, and so 

 far as my very limited experience shows the elongate cirri of many P. marmoraius do not appear on the 

 Califomian form, although the symmetrical arrangement of the tubercles is much the same. 



Ortmann (1891, p. 672) has suggested that Hoyle 's species may after all be identical with O. hawaii- 

 ensis Souleyet, in which case the latter name has many years priority and would of course take pre- 

 cedence, but for the present the matter must go over unsettled. 



One of the Challenger specimens, which is the largest example of the species so far recorded, has 

 a total length of 630 mm. The species is apparently an abundant littoral form occurring in large num- 

 bers on the reefs, and is one of the most important of the species used as food. As the most common 

 of the Polypi it is likely to be met with in almost any general collection from the region. It is readily 

 distinguishable from the species which usually accompany it by its somber coloration, ridgelike cirri, 

 moderate arms, small hectocotylus, and wide funnel organ, as well as the presence of the three cirri 

 over the eyes and the oculations at the base of the third arms. Being a solid and muscular species, 

 the tissues, particularly of the arms, are apt to undergo a powerful contraction when preserved in 

 alcohol. 



